In the title compound, C(9)H(7)N(3)O(3)S, the nitro and thia-zolidinone moieties are inclined with respect to the aromatic ring at dihedral angles of 9.57 (16) and 78.42 (4)°, respectively. In the crystal, N-H⋯O hydrogen bonding connects the mol-ecules along the c and a axes to form a two-dimensional polymeric network. A weak S⋯O inter-action [3.2443 (11) Å] and phenyl ring to phenyl ring off-set π⋯π stacking [with centroid-centroid separation of 3.6890 (7) Å and ring slippage of 1.479 Å] link the polymeric chains along the b and a axes, respectively.