The title compound, poly[aqua(μ(2)-1H-imidazole-4-carboxylato-κ(3)N(3),O:O')hemi(μ(2)-oxalato-κ(4)O(1),O(2):O(1'),O(2'))cadmium(II)], [Cd(C(4)H(3)N(2)O(2))(C(2)O(4))(0.5)(H(2)O)](n), exhibits a two-dimensional network. The Cd(II) cation is coordinated to one N atom and two carboxylate O atoms from two 1H-imidazole-4-carboxylate (Himc) ligands, two carboxylate O atoms from the bridging oxalate anion and one ligated water molecule; these six donor atoms form a distorted octahedral configuration. The oxalate anion lies on a centre of inversion. The Himc ligands connect the Cd(II) cations to form -Cd-Himc-Cd-Himc-Cd- zigzag chains, with a Cd···Cd separation of 5.8206 (6) Å along the b direction, which are further linked by tetradentate oxalate anions to generate a two-dimensional herringbone architecture in the ab plane. These layers are extended to form a three-dimensional supramolecular framework via O-H···O and N-H···O hydrogen bonds and π-π stacking interactions. The solid-state photoluminscent behaviour of the title compound has been investigated at room temperature.