In the title compound, C15H12N2S2, the two phenyl rings and the planar (r.m.s. deviation = 0.002 Å) thia-diazole ring adopt a propeller conformation about the central C-H axis with H-C-C-C(phen-yl) torsion angles of 44 and 42° and an H-C-N-C(thia-diazole) torsion angle of 28°. Intra-molecular C-H⋯S and C-H⋯N contacts are observed. In the crystal, centrosymmetrically related mol-ecules associate through C-H⋯π inter-actions. These are connected into a supra-molecular chain along [101] by C-H⋯N inter-actions.