A novel three-dimensional metal–organic framework [Ni3(BTC)2(bpp)2(H2O)]·3H2O (1) based on mixed ligands H3BTC (1,2,4-benzenetricarboxylic acid) and bpp (1,3-bis(4-pyridyl)propane) was obtained under hydrothermal conditions. Crystal structure analysis reveals that 1 is a framework based on cage-like Ni8(COO)12 units. Furthermore, long-range magnetic ordering is observed at low temperature.

A cobalt-1,4-naphthalenedicarboxylic acid system in a systematic series of ionic liquids with different alkyl chain lengths of imidazolium cations governed the construction of four MOFs with regular changes of secondary building units (SBUs).

•One carboxylate-functionalized luminescent phosphomolybdate has been synthesized.•The compound has been characterized by 31P NMR, UV–vis, XRPD and elemental analysis.•X-ray single-crystal structure analysis and discussion for the compound.•The compound exhibits a sensitive and reversible fluorescence response to the pH values in H2O solution.One inorganic–organic hybrid phosphomolybdate H12[(PMo6O21)2(1,4-NDC)3]·37.5H2O (1) (1,4-H2NDC=1,4-naphthalenedicarboxylic acid) has been synthesized and well-characterized. Compound 1 exhibits a lantern-type dimer constructed by Mo−O−C bonds between a couple of [PMo6O21]3− polyoxoanions and three 1,4-NDC2− ligands, and displays obvious fluorescent emission at room temperature as a result of the use of functional organic component. The spectroscopic experiments show that compound 1 displays a sensitive and reversible fluorescence response to the pH values in the aqueous solution.

A new Sr(II) coordination polymer (EMIm)4[Sr10(1,4-NDC)10Br4] 1 has been ionothermal synthesized using 1-ethyl-3-methylimidazolium bromide as solvent and characterized by IR, elemental analysis, XRPD and X-ray crystallography, where 1,4-H2NDC is 1,4-naphthalenedicarboxylic acid. Polymer 1 displays a crystalline 3D framework, in which the anions of 1,4-H2NDC are embedded in three bridging coordination modes and Sr(II) centers show five coordination geometries. Each dodecanuclear metallocyclic ring segment formed by distorted edge-sharing and face-sharing Sr coordination polyhedra extends out to increase the dimensionality by strontium coordination polyhedra sharing to obtain a rare Sr-based 2D sheet. Organic bridging ligands connect adjacent layers giving rise to a 3D structure and (EMIm)+ cations acting as extra charge balancing species occupy the channels of the anionic framework. The luminescent properties of polymer 1 at room temperature were investigated.

•One novel 3D polymer constructed from infrequent μ–O cobalt chains has been synthesized.•The polymer has been characterized by IR, XRPD, TG and elemental analysis.•X-ray single-crystal structure analysis and discussion for the polymer.•Magnetic property analysis of 1 indicates an intrachain alternating antiferromagnetic/ferromagnetic coupling.One novel metal–organic framework of formula {[Co2(1,4-NDC)2(4,4′-dpdo)(H2O)]·3H2O}n1 (1,4-H2NDC = 1,4-naphthalenedicarboxylate acid and 4,4′-dpdo = 4,4′-dipyridyl-N,N′-dioxide) has been synthesized, and structurally and magnetically characterized. X-ray single crystal structure shows that polymer 1 exhibits a 3D metal–organic framework containing alternating metal chains with two kinds of triple bridge (two carboxylate plus μ–4,4-dpdo or μ–H2O). The metal centers exhibit somewhat distorted octahedral surroundings with two opposite vertexes shared with the adjacent in the chain. Each alternating chain segment is cross-linked to four other different chains through four 1,4-NDC2− ligands to form the 3D structure. The variable-temperature magnetic susceptibility of 1 was investigated in the temperature range of 1.8–300 K. The magnetic coupling behavior between metal atoms can be estimated with the model developed by Fisher for an alternating chain of classical spins. The result indicates that it could be considered as an alternating chain with –AF–FM–AF–FM– interaction.

•Two novel POM-based compounds have been synthesized with silver–azines.•The compounds have been characterized by IR, UV, XRPD and elemental analysis.•X-ray single-crystal structure analyses and discussion for the compounds.•The two compounds exhibit fluorescent emission in solid state, respectively.Two polyoxometalate-based inorganic–organic hybrid compounds constructed from silver(I)-L species and saturated Keggin type polyoxoanion, [Ag2L21]2(SiMo12O40)·1.5DMF·0.5CH3OH⋅H2O 1 and [{Ag4L22(DMF)5}(SiMo12O40)] 2 (L1 = phenyl 2-pyridyl ketone azine, L2 = 3-phenyltriazolo[1,5-a]pyridine), have been synthesized and structurally characterized by IR, UV, elemental analysis, XRPD and complete single crystal structure analyses, where the ligands L1 and L2 are bis-bidentate and tridentate azines synthesized with the same materials under different conditions. The structure of 1 exhibits a dinuclear double-helicate with [SiMo12O40]4− anions as counter ions, where all of the Ag centers coordinate to bis-bidentate chelating ligands. Compound 2 displays a two-dimensional sheet formed by the Ag–organic infinite chains and the [SiMo12O40]4− alternately arranged in a “rail-like” fashion. The luminescent properties of 1 and 2 in the solid state were investigated.Graphical abstract

•Two versatile 3D polymers have been synthesized with d10 metal ions.•IR, PXRD, TG technique for the polymers.•X-ray single-crystal structure analyses and discussion for the polymers.•The polymers exhibit interesting luminescence properties in solid state.Hydrothermal reactions of d10 metal ions (Cd2+ and Zn2+) with 1,4-naphthalenedicarboxylate acid (1,4-H2NDC) and 4,4′-dipyridyl N,N′-dioxide (4,4′-dpdo) form two three-dimensional grid-like coordination polymers [Cd2(1,4-NDC)2(4,4′-dpdo)]·H2O 1 and [Zn4(μ3-OH)2(1,4-NDC)3(H2O)2](4,4′-dpdo)·2H2O 2. Both coordination polymers were characterized by single crystal X-ray diffraction, IR spectroscopy, XRPD, thermogravimetric and elemental analyses. Polymer 1 exhibits rare alternating arranged 1,4-NDC2− and 4,4′-dpdo spacers between adjacent 1D zigzag chains containing Cd-octahedral coordination geometries. Polymer 2 is constructed from infrequent chair-like [Zn4(μ3-OH)2]6+ inorganic SBUs with four- and six-coordination geometries and only 1,4-NDC2− as “single-bridge” and “double-bridges” to form a 3D framework. Both polymers give strong luminescent emissions in the solid state at room temperature.

•Designed and synthesized a new dicoumarol-based fluorescent compound.•Crystal structure analyses and discussion for the compound.•The compound exhibits a highly fluorescence-quenching selectivity for FeIII.A new dicoumarol-based compound (C6H4)[CH2NHCO(C9O2H4)N(C2H5)2]21 was synthesized and characterized by IR, UV spectroscopy and single-crystal X-ray diffraction analysis. The structure of 1 exhibits a transoid formation with the two coumarin-containing arms sited on the two sides of the center benzene ring. In the crystal packing the molecule further interact with each other and form a three-dimensional framework through π–π stacking interactions and multiform hydrogen bonds. The compound 1 shows the main emission peak at 540 nm corresponding to the green hue in the solid state. The fluorescence recognition behaviors for various metal ions were investigated and 1 exhibits a highly fluorescence-quenching selectivity for FeIII ion in the mixed CH3CNH2O solvent.Graphical abstract

•Two new polyoxometalate-based polymers have been synthesized.•Polymers exhibit a 3D supramolecular network decorated with Keggin anions.•The fluorescent properties were investigated in the solid state.Two polyoxometalate-based coordination polymers {[Mn2(dpdo)4(H2O)6](GeMo12O40)(H2O)4}n (1) and {[Mn2(dpdo)4(H2O)6](GeW12O40)(H2O)3}n (2) (dpdo = 4,4′-bipyridine-N,N′-dioxide) have been synthesized and characterized by IR, elemental analysis, XRPD, TG technique and X-ray crystallography. The polymers 1 and 2 are basically isostructural and feature a 3D supramolecular framework decorated with Keggin-type polyanion clusters based on one-dimension polymeric chains, which formed through the coordination interaction of Mn(II) and dpdo. The luminescent properties of the polymers were investigated in the solid state at room temperature.Graphical abstract

Four new inorganic–organic hybrid coordination polymers {[Ag2L(NO3)2]·H2O}n (1), [Ag2L(SCN)2]n (2), [CdL(SCN)2]n (3), and [CdLI2]n (4) have been synthesized and structurally characterized by IR spectroscopy, thermogravimetric (TG) analyses and complete single crystal structure analyses, where L is 2,5-bis(pyrazinyl)-3,4-diaza-2,4-hexadiene. The structure of polymer 1 is a 3D coordination framework containing Ag-(μ-NO3−) inorganic bridging units, in which each L coordinates four silver atoms through two pyrazinylimine chelate units and two terminal monodentate pyrazinyl N donors. Polymer 2 displays a new 3D inorganic–organic hybrid network through the coordination interactions between Ag-(1,1,3-μ-SCN−) inorganic 2D sheets and bidentate bridging ligands with two terminal monodentate pyrazinyl N donors. Bidentate bridging ligands link 1D inorganic chains Cd-(1,3-μ-SCN−) system for 3 and Cd-(μ-I−) system for 4 to form a similar two-dimensional layer network. The luminescent properties of polymers 1–4 were investigated in the solid state at room temperature.

A 2D Wells–Dawson-based silver(I) coordination polymer was achieved based on silver-Schiff base building blocks and [P2Mo18O62]6− clusters using AgNO3, N,N′-bis(furan-2-ylmethylene)hydrazine and Keggin [PMo12O40]3− as original materials at room temperature. It is structurally characterized by IR spectroscopy, 31P NMR, XRPD, thermogravimetric (TG) analyses and X-ray crystallography. The structure of 1 exhibits a novel crystalline 2D coordination polymer constructed by the coordination interaction between the Wells–Dawson polyoxoanion [P2Mo18O62]6− and Ag–L species. The luminescent property of 1 in the solid state is investigated.

Two new copper coordination polymers [CuI2L(SCN)2]n (1) and {[CuIIL2(NO3)2]·2H2O}n (2), have been synthesized and characterized by IR, elemental analysis, XRPD, TG technique and X-ray crystallography, where L is N,N′-bis-(1-pyridin-4-yl-ethylidene)-hydrazine. Polymer 1 displays a new 3D inorganic–organic hybrid network generated through the coordination interactions between 2D inorganic sheets Cu(I)-(1,1,3-μ-SCN−) and bidentate bridging ligands L with two terminal monodentate pyridyl N donors. Each Cu(I) center adopted a distorted tetrahedral environment. The structure of polymer 2 is a 2D layer network containing tetrametallic quadrangular ring units [CuII4L4], in which each copper(II) atom is linked by four terminal monodentate pyridyl N-donors from four twist ligands and two oxygen atoms from two NO3−. The luminescent properties of polymers 1 and 2 were investigated in the solid state at room temperature.Graphical abstractHighlights► Two copper coordination polymers have been synthesized. ► The polymers have been characterized by IR, XRPD, TG technique. ► Polymer 1 displays a 3D network and polymer 2 is a 2D layer structure. ► The two polymers exhibit fluorescent emission in solid state, respectively.

Two two-dimensional d10-metal-organic frameworks {[CdL2(NO3)2]·(H2O)6}n (1) and {[Zn2L4(NCS)4]·(H2O)4·(CH3OH)}n (2) have been synthesized and characterized by IR, elemental analyses, XRPD, TG technique and complete X-ray single crystal structure analyses, where L is bis(pyridin-3-ylmethylene)biphenyl-2,2′-dicarbohydrazide. The two polymers display similar 2D layer network containing tetranuclear metallacyclic ring units [MII4L4] (M = Cd (1) and Zn (2)) in the chair conformation, in which each ligand L acts as a bidentate bridging ligand to bind two metal centers through two terminal pyridyl N-donors. The solvent molecules were filled into the macrometallacyclic ring units through multiform hydrogen bonds. In addition, the CH⋯π interactions are found in the 2D networks and also play an important role in stabilizing the networks. The luminescent properties of 1 and 2 were investigated in the solid state at room temperature.Graphical abstractHighlights► Two d10-metal-organic frameworks have been synthesized. ► The polymers have been characterized by IR, XRPD, TG technique. ► The polymers display similar 2D network containing tetrametallic rings [MII4L4]. ► The two polymers exhibit fluorescent emission in solid state, respectively.

Two one-dimensional d10-metal coordination polymers {[AgL(H2O)]2[AgL(NO3)]2(NO3)2L(H2O)2}n (1) and [ZnLCl2]n (2) (L = N,N′-bis-(1-pyridin-4-yl-ethylidene)-hydrazine) have been synthesized and characterized by IR, elemental analysis, TG technique, XRPD and X-ray crystallography. Polymer 1 contains two types of 1D Ag-double-chain units. Ag(1)-double-chain unit is formed by linking two adjacent Ag(1)-L-chains through face-to-face π⋯π interactions, while Ag(2)-double-chain unit is formed through the combination of coordinating NO3− anions bridging interactions and π⋯π interactions between two adjacent Ag(2)-L-chains. Free ligands interact with the adjacent Ag(1)-double-chain units and Ag(2)-double-chain units to form a 3D supramolecular structure through multiform hydrogen bonds. For polymer 2, each ligand acts as a bis-monodentate bridging ligand to bind adjacent Zn(II) centers forming a one-dimensional chain structure. Furthermore, 1D chain is held together with its neighboring ones via CH⋯π interactions. The luminescent properties of the polymers 1 and 2 were investigated in the solid state at room temperature.Graphical abstractHighlights► Two d10-metal polymers have been synthesized with Schiff-base ligand. ► The polymers have been characterized by IR, elemental analysis, TG technique. ► X-ray single-crystal structure analyses and discussion for the polymers. ► The luminescent properties of the polymers were investigated in solid state.

Two new one-dimensional coordination polymers {[CdL2(H2O)2](NO3)2(H2O)6}n (1) and {[CdLI2](H2O)(CH3OH)}n (2) have been synthesized and characterized by IR, elemental analysis, TG technique, XRPD and complete single crystal structure analyses, where L is bis(pyridin-4-ylmethylene)biphenyl-2,2′-dicarbohydrazide. The Cd(II) atom has a distorted octahedral coordination geometry with N4O2 donors from four ligands and two water molecules in 1 and a distorted tetrahedral coordination geometry with NOI2 donors from two ligands and two I− anions in 2, respectively. Polymer 1 shows a 1D framework structure containing bimetallic 42-membered quadrangular ring units. The adjacent 1D chains are interacted forming a 3D supramolecular network structure through multiform hydrogen bond interactions. In comparison with 1, polymer 2 is a new rampart-type chain and each chain is interacted with each other through hydrogen bond interactions to lead a 2D layer. The luminescent properties of the polymers 1 and 2 were investigated in the solid state at room temperature.Graphical abstractHighlights► Two cadmium(II) polymers have been synthesized. ► IR, PXRD, TG technique for the polymers. ► X-ray single-crystal structure analyses and discussion for the polymers. ► The polymers exhibit interesting luminescence properties in solid state.

Three polyoxometalate-based inorganic–organic hybrid compounds constructed from silver(I)-L (L = N,N′-bis-pyridin-2-ylmethylene-hydrazine) species and saturated Keggin type polyoxoanions, {[Ag3L3](PW12O40)(CH3CN)(DMF)2.5}n (1), [Ag4L3(CH3CN)4][Ag2L(CH3CN)3](PMo12O40)2·CH3CN (2) and [(SiMo12O40){Ag2L(CH3CN)3}2]·(CH3CN)2 (3), have been synthesized and structurally characterized by IR spectroscopy, UV spectroscopy, thermogravimetric (TG) analyses and complete single crystal structure analyses. The structure of 1 containing [PW12O40]3− anions as templates exhibits a one-dimensional chain structure constructed by the coordination of a silver center and bis-bidentate bridging ligands with the pyridyl rings adopting a transoid configuration. Compound 2 displays an AB-type arrangement supramolecular structure, in which A is a two-dimensional sheet formed by linking the adjacent [Ag4L3(CH3CN)4]4+ units through the cooperativity of intermolecular π–π interactions and C–H⋯π interactions, while B is composed of [PMo12O40]3− anions and binuclear [Ag2L(CH3CN)4]2+ cations. Compound 3 exhibits a new bisupporting Keggin-polyoxometalate structure in which the [SiMo12O40]4− core supports two [Ag2L(CH3CN)3]2+ fragments in two opposite positions. The luminescent properties of L and 1–3 in the solid state were investigated.

Two new copper(II) complexes Cu(NCS)2(4-Bzpy)2 (1) and Cu(NO3)2(4-Bzpy)4 (2) (4-Bzpy = 4-benzoylpyridine) have been synthesized and characterized by IR, UV, elemental analysis and X-ray crystallography. Cu(II) atom has a square planar environment for 1 and an distorted octahedral environment for 2, respectively. In solid state there are C–H⋯π interactions and C–H⋯S hydrogen bonds between adjacent molecules in complex 1. The molecule of complex 2 is further connected by multiform π–π interactions, C–H⋯π interactions and C–H⋯O hydrogen bonds to form a three-dimensional supramolecular structure. The luminescent properties of the complexes 1 and 2 were both investigated in H2O solution and in solid state at room temperature, respectively.Graphical abstractHighlights► Two new copper(II) complexes have been synthesized. ► IR, UV, elemental analysis for the complexes. ► X-ray single-crystal structure analyses and discussion for the complexes. ► The luminescent properties of the complexes in H2O solution and in solid state.

A new inorganic–organic hybrid compound [FTMA]2[Co(NCS)4] (FTMA = ferrocenylmethyltrimethylammonium cation) has been synthesized and characterized by IR, UV, elemental analysis and X-ray crystallography. Co(II) atom has a distorted tetrahedral environment with four N atoms of four NCS− anions. In the solid state there are C–H⋯π interactions between adjacent ferrocenyl cations, which generate one-dimensional (1-D) supramolecular chain, and C–H⋯S hydrogen bonds between [FTMA]+ cations and cobalt thiocyanate anions. The title compound shows strong purple fluorescence emission in the solid state at room temperature.Graphical abstractHighlights► A new inorganic–organic hybrid compound have been synthesized. ► It was characterized by IR, UV, elemental analyses and X-ray single crystal diffraction. ► The compound shows strong purple fluorescence emission in solid state.

A new inorganic–organic hybrid compound [O2NBzQL]4[Cd(SCN)4(NCS)2] (O2NBzQL = 1-(4′-NO2-benzyl)quinolinium cation) has been synthesized and characterized by IR, UV, elemental analysis and X-ray crystallography. Cd(II) atom has an distorted octahedral environment with an N4S2 donor set. In solid state there are three types of face-to-face π–π interactions between adjacent cations and multiform C–H⋯S and C–H⋯N hydrogen bonds between [O2NBzQL]+ cations and cadmium thiocyanate anions. The luminescent properties of the title compound were both investigated in H2O solution and in solid state at room temperature, respectively.

A series of metal–organic frameworks {[AgL1]ClO4}n (1), {[AgL12]BF4}n (2), {[AgL1(NO3)](CH3CH2OH)}n (3), {[ZnL12(NCS)2]CH3CN}n (4), [AgL2(NO3)]n (5), {[FeL22Cl2]·CH3CN}n (6), {[MnL22(NCS)2]·(CH3CH2OH)}n (7) and [ZnL22(NCS)2]n (8) have been synthesized and structurally characterized by IR spectroscopy, UV spectroscopy, thermogravimetric (TG) analyses, luminescent spectroscopy and complete single-crystal structure analyses, where L1 is (N′,N′-bis[1-(pyridin-4-yl)methylidene]benzil dihydrazone) and L2 is (N′,N′-bis[1-(pyridin-3-yl)methylidene]benzil dihydrazone), respectively. The structure of 1 exhibits a two-dimensional layer network featuring trimetal 36-membered non-planar macrocycles. Polymer 2 is a one-dimensional chain structure with tetranuclear metallacyclic rings. For polymer 3, each ligand acts as a bidentate ligand to bind two Ag(I) centers and each silver center is coordinated to two N-donors from two ligands forming a one-dimensional chain. Polymer 4 displays a two-dimensional layer network containing tetranuclear 68-membered metallocyclic rings. Polymers [AgL2(NO3)]n (5), {[FeL22Cl2]·CH3CN}n (6), {[MnL22(NCS)2]·(CH3CH2OH)}n (7) and [ZnL22(NCS)2]n (8) show all one-dimensional chain structures containing bimetallic 8-membered rings and tetrametallic 42-membered rings for 5, bimetallic 34-membered quadrangular rings for 6 and 7, and bimetallic 30-membered quadrangular rings for 8, respectively. The luminescent properties of L1, L2 and 1–8 in the solid state were investigated.

The polyoxometalate-based 1D coordination polymer [Cu(DMF)6][PMoVMoVI11O40Cu(DMF)4]·DMF 1 was synthesized and characterized by IR, UV spectroscopy and single-crystal X-ray diffraction analysis. Each Cu(II) center has a distorted octahedral coordination geometry. Cu(1) center interconnects with two [PMoVMoVI11O40]4− anion subunits and each [PMoVMoVI11O40]4− polyoxoanion acts as a didentate ligand to link two Cu centers through two terminal oxygen atoms to form a one-dimensional chain structure. The luminescent properties of 1 in the solution and in the solid state were investigated, respectively.

The heteronuclear coordination polymer [Cd(SCN)2Ni(en)(NCS)2(EtOH)]21 (en = ethylenediamine) was obtained by reaction of Cd(NO3)2·4H2O, KSCN, Ni(NO3)2·6H2O and en in a mole ration of 1:3:1:0.1 in ethanol solution. The complex is characterized by IR spectroscopy, electronic spectroscopy and single-crystal X-ray diffraction analysis. Crystal structure analyses show that the title complex belongs to the triclinic space group P1¯ with a = 8.922(3), b = 9.860(3), c = 10.333(5) Å, α = 113.116(6)°, β = 106.550(6)°, γ = 101.622(4)°, V = 749.0(5) Å3. Cd(II) and Ni(II) centers are linked by di-μ-1,3-thiocyanate bridges to form a 2D network containing three types of 16-membered [Cd2Ni2(μ-1,3-SCN)4] macrocycles. Each Cd(II) center links six Ni(II) centers by six μ-1,3-SCN− bridges and each Ni(II) center links three Cd(II) centers by three μ-1,3-SCN− bridges. The luminescent properties of 1 in the solid state were investigated.

A novel Cd(II) coordination polymer [Cd(SCN)2(hmt)1/2(H2O)]2·H2O (hmt = hexamethylenetetramine) has been synthesized and characterized by IR, elemental analysis, TG technique and X-ray crystallography. Cd(II) atom has an distorted octahedral environment with an N3S2O donor set. Every six Cd(II) centers are linked by hmt and thiocyanato bridges to form a planar 2D coordination polymer containing hexagonal metallocyclic rings [Cd6(SCN)8(hmt)2]. A 2D layer structure is held together with its neighboring ones via a set of hydrogen-bonding interactions to form a 3D supramolecular structure. The luminescent properties of the title complex in the solid state were investigated.

A novel heteronuclear polymeric complex Cd(SCN)3Cu(en)2NO3 (1) (en = ethylenediamine) has been synthesized and structurally characterized. The Cd(II) atom is surrounded by three S atoms and three N atoms from four 1,3-μ-SCN− and two 1,1,3-μ-SCN− to attain a distorted octahedral coordination geometry. Six Cd(II) centers are linked by twelve thiocyanato bridges to form hexagonal metallocyclic unit [Cd6(SCN)12] and extend a 2D network. Moreover, a 1,1,3-μ-SCN− links two cadmium and one copper metal atoms. The luminescent properties of 1 in the solid state were investigated.A thiocyanato bridged heteronuclear polymer Cd(SCN)3Cu(en)2NO3 (en = ethylenediamine) was presented. 2D networks of the complex is achieved by the two bridge modes of 1, 3-μ-SCN− and 1,1,3-μ-SCN− between Cd(II) and Cu(II) centers. The 2D layers was further interacted each other feathering 3D network through multiform hydrogen bonds.

A 2D Wells–Dawson-based silver(I) coordination polymer was achieved based on silver-Schiff base building blocks and [P2Mo18O62]6− clusters using AgNO3, N,N′-bis(furan-2-ylmethylene)hydrazine and Keggin [PMo12O40]3− as original materials at room temperature. It is structurally characterized by IR spectroscopy, 31P NMR, XRPD, thermogravimetric (TG) analyses and X-ray crystallography. The structure of 1 exhibits a novel crystalline 2D coordination polymer constructed by the coordination interaction between the Wells–Dawson polyoxoanion [P2Mo18O62]6− and Ag–L species. The luminescent property of 1 in the solid state is investigated.

A cobalt-1,4-naphthalenedicarboxylic acid system in a systematic series of ionic liquids with different alkyl chain lengths of imidazolium cations governed the construction of four MOFs with regular changes of secondary building units (SBUs).