The title compound, C(7)H(5)NSSe, is the product of the reaction of 2-chloro-benzothia-zole with sodium hydro-selenide. The mol-ecule is almost planar (r.m.s. deviation = 0.018 Å) owing to the presence of the long chain of conjugated bonds (Se=C-N-C=C-C=C-C=C). The geometrical parameters correspond well to those of the analog N-methyl-benzothia-zole-2(3H)-selone, demonstrating that the S atom does not take a significant role in the electron delocalization within the mol-ecule. In the crystal, mol-ecules form centrosymmetric dimers by means of inter-molecular N-H⋯Se hydrogen bonds. The dimers have a nonplanar ladder-like structure. Furthermore, the dimers are linked into ribbons propagating in [010] by weak attractive Se⋯S [3.7593 (4) Å] inter-actions.