In the title compound, C(11)H(10)ClN(3)S, the dihedral angle between the benzene and pyrimidine rings is 3.99 (4)°. In the crystal, inter-molecular N-H⋯N hydrogen bonds link the mol-ecules into ribbons of R(2) (2)(8) rings parallel to [100]. Weak C-H⋯S contacts connect adjacent ribbons into a two-dimensional undulating layer-like structure extending parallel to (110). The benzene and pyrimidine rings of adjacent mol-ecules have the offset face-to-face π-π stacking inter-actions in a zigzag fashion along the c axis, with perpendicular ring distances of 3.463 and 3.639 Å, and a dihedral angle between the planes of 3.99 (2)°. The distance between the ring centroids is 4.420 (2) Å.