In the title compound, C(19)H(21)N(3)O(2)S, the dihedral angle between the aromatic rings is 6.7 (2)° and the C=N-N=C torsion angle is 178.0 (2)°. The conformation of the thia-zine ring is an envelope, with the S atom displaced by 0.802 (2) Å from the mean plane of the other five atoms (r.m.s. deviation = 0.022 Å). In the crystal, mol-ecules are linked by C-H⋯O inter-actions, generating C(5) chains propagating in [010]. A weak C-H⋯π inter-action is also observed.