In the mol-ecule of the title compound, C(14)H(8)Cl(2)N(4)S, all the ring atoms in the pyrazolopyrimidine system are almost coplanar, the largest deviation from the mean plane being 0.027 (2) Å for a C atom. The conformation of the methyl-sulfanyl group is anti-periplanar, with a torsion angle of -176.7 (2)°. A weak inter-molecular C-H⋯N hydrogen bond and a Cl⋯N halogen bond [Cl⋯N = 3.196 (5) Å] with a nearly linear N⋯Cl-C angle [174.2 (1)°] link the mol-ecules into a two-dimensional assembly. Face-to-face π-π stacking, with a centroid-centroid separation of 3.557 (2) Å and an angle of 7.1 (1)° between the two planes, completes the inter-molecular inter-actions in the solid state.