In the title compound, C(13)H(12)N(4)S, an amino N atom is connected to a 1,3-benzothia-zole fused-ring system and a dimethyl-substituted pyrimidine ring, these components being aligned [inter-planar dihedral angle = 1.9 (1)°]. The secondary amino N atom forms an inter-molecular N-H⋯N hydrogen bond to an N atom of the fused ring of an adjacent mol-ecule, generating a centrosymmetric cyclic hydrogen-bonded dimer [graph set R(2) (2)(8)].