2,9-Di-methyl-phenanthro[2,1-b:6,5-b']di-thio-phene.

The title compound, C20H14S2, was synthesized from a dimethyl-substituted thio-phene precursor using an oxidative photocyclization reaction. The mol-ecule has a puckered structure due to steric crowding and the extended structure is consolidated by C-H⋯π inter-actions between columns of stacked mol-ecules.