The title compound, C17H10S4, has two independent molecules in the asymmetr
ic unit. In both molecules, the fused heterocycle is almost planar and the
phenyl groups make dihedral angles of 42.88 (9) and 52.79 (8)degrees with t
he fused heterocycle in one molecule, and angles of 40.62 (9) and 52.28 (8)
degrees in the other. The crystal packing is governed by short intermolecul
ar S . . .S interactions, the shortest contact being 3.333 (1) Angstrom.