catena-Poly[[(2,2'-bipyridine-κN,N')cadmium]-μ(3)-4-nitro-phthalato-κO:O',O'':O'''].

In the title polymeric compound, [Cd(C(8)H(3)NO(6))(C(10)H(8)N(2))](n), two O atoms from both carboxyl-ate groups of a nitro-phthalate anion coordinate to the Cd(II) cation, forming a seven-membered chelate ring and two carboxyl-ate O atoms from another two nitro-phthalate anions and a 2,2'-bipyridine ligand coordinate to the Cd cation to complete the distorted octa-hedral coordination geometry. The carboxyl-ate groups of the nitro-phthalate anion adopt a syn-anti bridging mode, linking adjacent Cd(II) cations and forming a polymeric chain running along the a axis. Weak intra- and inter-molecular C-H⋯O hydrogen bonding is present in the crystal structure.