Accessing π‐expanded heterocyclics beyond dibenzothiophene: Syntheses and properties of phenanthrothiophenes.

A series of phenanthrothiophenes are designed and synthesized from polyarylthiophenes through regioselective Scholl reactions in one step using iron chloride as catalyst. The molecular structures of these heteroarenes displayed multiple twisted fjords, which perturb the shapes of the polycyclic frameworks to pack in slipped to near‐perfect face‐to‐face styles in parallel or antiparallel packings. Field‐effect transistor devices using single crystals of 6,12‐difluorodiphenanthro[9, 10‐b:9′, 10′]thiophene gave a hole mobility of 0.22 cm2 V−1 s−1. [ABSTRACT FROM AUTHOR]