In the title compound, C10H8N4S2, comprising fused six-, six- and five-membered rings, the mol-ecule is close to being planar (r.m.s. deviation of the non-H atoms = 0.041 Å). The S-bound methyl group is folded away from the single N atom of the triazole ring and the NH group of the six-membered ring, allowing for the formation of centrosymmetric eight-membered {⋯HNCN}2 synthons in the crystal. The resulting inversion dimers are connected into supra-molecular stacks aligned along the b-axis direction by π-π inter-actions [centroid-centroid distances = 3.6531 (12) and 3.7182 (12) Å].