In the mol-ecule of the title compound, C(19)H(18)N(4)O(3)S, the planar central heterocylic ring system is oriented with respect to the trimethoxy-phenyl and 2-methyl-phenyl rings at dihedral angles of 4.43 (3) and 4.32 (3)°, respectively. The dihedral angle between the two benzene rings is 7.65 (4)°. In the crystal structure, inter-molecular C-H⋯N hydrogen bonds link the mol-ecules into centrosymmetric R(2) (2)(18) dimers. These dimers are connected via a C-H⋯π contact between the 2-methyl-phenyl and trimethoxy-phenyl rings, and a π-π contact between the thia-diazole and trimethoxy-phenyl rings [interplanar distance 3.51 Å, dihedral angles 4.17(4)°]. An intramolecular C-H⋯N hydrogen bond is also present.