Synthesis, crystal structure and Hirshfeld surface analysis of 7-oxo-6-phenyl-6,7-dihydro-5H-thieno[2,3-f]isoindole-8-carboxylic acid

In the title compound, C17H11NO3S, the thieno[2,3-f]isoindole ring system and the phenyl ring are oriented at a dihedral angle of 20.57(13)°. The strong intramolecular O - H⋯O hydrogen bond partly ensures the coplanarity of the carboxyl group and the ring system. In crystal, the molecules are linked through C - H⋯O hydrogen bonds, enclosing R22(14) ring motifs, into a three-dimensional architecture. π-π interactions between parallel five-membered and phenyl rings [centroid-to-centroid distances of 3.564(3) and 3.591(3)Å] further contribute to the cohesion of the crystal structure. The Hirshfeld surface analysis indicates that the most important contributions for the crystal packing are from H⋯H (35.5%), H⋯O/O⋯H (21.3%), C⋯C (14.1%) and H⋯C/C⋯H (12.8%) interactions. © 2025 International Union of Crystallography. All rights reserved.