In the title hydroxamic acid derivate, C(21)H(14)N(2)O(5)Cl(2), the nitro-substituted benzene ring forms dihedral angles of 66.0 (2) and 59.6 (2)°, with the p-chloro and o-chloro-substituted benzene rings, respectively. The dihedral angle between the two chloro-substituted benzene rings is 64.2 (2) Å. In the crystal, weak C-H⋯O hydrogen bonds link the mol-ecules along [010]. The crystal studied was an inversion twin with refined components in the ratio 0.60 (7):0.40 (7).