Three-directional annulations of isobenzofuran trimer equivalent are developed. Importantly, the successive cycloadditions could be controlled under suitable conditions, selectively affording the dual or triple cycloadduct, which leads to the alternative preparation of the symmetrical and unsymmetrical star-shaped polycyclic aromatic ketones. 1H NMR analysis of the star-shaped aromatic ketone indicated the π–π interactions through the aggregation in solution.

Ring selective generation of isobenzofuran, a formal equivalent to bis-isobenzofuran, was developed. Importantly, selective introduction of functionalities and/or fused rings in the isobenzofuran core by iterative cycloadditions can achieve the divergent construction of polycyclic compounds. This selective approach enables us to prepare a regioisomeric pair of pentacenes.

Stereoselective [4+2] cycloadditions of 1,4-dihydro-1,4-epoxynaphthalene and isobenzofuran were described. Among several possibilities, syn–exo and/or anti–endo isomers were selectively produced depending on the substitution pattern of the reactants. Importantly, the syn–exo isomer underwent acid promoted aromatization, affording the corresponding tetracene. These findings enabled us to prepare a substituted pentacene with electron withdrawing groups.

Two-directional annulation of dibromoisobenzofuran, a formal equivalent to didehydroisobenzofuran, was developed. Importantly, selective bromine–lithium exchange allows the tandem generation of benzynes and dual cycloadditions with two different arynophiles. Also described is the application to the synthesis of a substituted pentacene.

An efficient synthetic method of 1,3-bis(arylethynyl)isobenzofurans is developed. Nucleophilic addition of alkynyllithium to benzocyclobutenone and subsequent oxidative ring cleavage of the four-membered ring gave a keto-aldehyde, which, in turn, accepted the second nucleophile to produce isobenzofurans after acid treatment.

Stereoselective [4+2] cycloadditions of 1,4-dihydro-1,4-epoxynaphthalene and isobenzofuran were described. Among several possibilities, syn–exo and/or anti–endo isomers were selectively produced depending on the substitution pattern of the reactants. Importantly, the syn–exo isomer underwent acid promoted aromatization, affording the corresponding tetracene. These findings enabled us to prepare a substituted pentacene with electron withdrawing groups.

An efficient synthetic method of 1,3-bis(arylethynyl)isobenzofurans is developed. Nucleophilic addition of alkynyllithium to benzocyclobutenone and subsequent oxidative ring cleavage of the four-membered ring gave a keto-aldehyde, which, in turn, accepted the second nucleophile to produce isobenzofurans after acid treatment.