The title compound, C(9)H(7)NS, crystallizes as the thione tautomer with Z' = 8 (four independent dimers with local inversion symmetry via two N-H...S=C hydrogen-bond systems). The dimers are arranged in chains parallel to [-110], each chain being crystallographically independent. These chains are associated into layers via stacking of ring systems. The Z' value can be rationalized in terms of a factor 2 for dimer formation without crystallographic symmetry and an additional factor 4 for differing stacking environments.