Multicolor luminescent films have great potential for use in optoelectronics, solid-state light-emitting materials, and optical devices. This work describes a systematic investigation of the ordered assembly of two- (blue/green, blue/orange, red/blue, red/green) and three-color (blue/red/green) light-emitting ultrathin films (UTFs) by using different photofunctional anions [bis(N-methylacridinium)@polyvinylsulfonate ion pairs and anionic derivatives of poly(p-phenylene), poly(phenylenevinylene), and poly(thiophene)] and Mg-Al-layered double hydroxide nanosheets as building blocks. The rational combination of luminescent components affords precise control of the emission wavelengths and intensity, and multicolored luminescent UTFs can be precisely tailored covering most of the visible spectral region. The assembly process of the UTFs and their luminescence properties, as monitored by UV–vis absorption and fluorescence spectroscopy, resulted in a gradual change in luminescence color in the selected light-emitting spectral region upon increasing the number of deposition cycles. X-ray diffraction demonstrates that the UTFs are periodic layered structures involving heterogeneous superlattices associated with individual photoactive anion–LDH units. These UTFs also exhibit well-defined multicolor polarized fluorescence with high polarization anisotropy, and the emissive color changes with polarization direction. Therefore, this work provides a way of fabricating heterogeneous UTFs with tunable-color luminescence as well as polarized multicolor emission, which have potential applications in the areas of light displays and optoelectronic devices.

Blue luminescent hybrid materials (DDS–AQS(x%)/LDH) are successfully prepared by co-intercalating tris(8-hydroxyquinoline-5-sulfonate)aluminum anions (AQS³⁻) and dodecyl sulfonate (DDS⁻) with different molar ratios into Mg–Al layered double hydroxides (LDHs) by the hydrothermal and solution co-precipitation methods. A film of the material on a quartz substrate is obtained by the solvent evaporation method. The results show the blue luminescence is remarkably different from the pristine Na₃AQS, which has cyan luminescence (ca. 450–470 nm vs. 495 nm). Furthermore, the hydrothermal product of DDS–AQS(66.67%)/LDH exhibits optimal luminous intensity and a significantly enhanced fluorescence lifetime. Nuclear magnetic resonance and Fourier-transform infrared spectroscopy indicate that the cyan–blue luminescence transition is due to the isomerization of meridianal to facial AQS via ligand flip caused by a host–guest electrostatic interaction, in combination with the dispersion and pre-intercalation effect of DDS. The hydrothermal conditions can promote a more ordered alignment of the intercalated fac-AQS compared with alignment in the solution state, and the rigid LDHs environment can confine the internal mobility of AQS to keep the facial configuration stable. This stability allows a facile preparation of large amounts of blue luminous powder/film, which is a new type of inorganic–organic hybrid photofunctional material.