The title mol-ecule, C(16)H(14)N(2)O(4)S, adopts an L-shaped conformation, with the central C-S-N-C torsion angle being -69.1 (3)°. The two benzene rings form a dihedral angle of 89.94 (15)°. The mol-ecular conformation may be influenced by a weak intra-molecular C-H⋯O hydrogen bond which generates an S(6) ring motif. In the crystal, mol-ecules are linked by N-H⋯O and weak C-H⋯O hydrogen bonds, forming chains propagating along the b axis. Weak C-H⋯N hydrogen bonds connect the chains into a two-dimensional network parallel to (011). The crystal studied was an inversion twin, the ratio of components being 0.7 (1):0.3 (1).