A new cadmium croconate (C5O52-) complex, [Cd-2(C5O5)(2)(4,4'-bpy)(H2O)](infinity) (4,4-bpy = 4,4'-bipyridine) with an extended network has been synthesized under hydrothermal conditions and characterized by single-crystal X-ray diffraction studies. The title compound crystallizes in the monoclinic system, space group P2(1)/n, with empirical formula C20H12Cd2N2O12, a = 15.9623(3) Angstrom, b = 7.5837(1) Angstrom, c = 18.1181(3) Angstrom, beta = 99.95(2)degrees, and Z = 4. Structural determination reveals that the title compound has a bilayered network, containing two crystallographically independent Cd(II) ions in different coordination environments. Cd(1) lies in a distorted pentagonal bipyramidal environment, consisting of three croconate ions and one 4,4'-bpy nitrogen donor, while Cd(2) lies in a distorted octahedral environment, consisting of two croconate anions, one 4,4'-bpy nitrogen donor, and one water molecule. Of the two crystallographic independent croconate ligands, one presents a bis-bidentate adjacent mu(3)-coordination mode and the other a new bidentate/three-adjacent mu(5)-coordination mode. A two-dimensional hybrid layer is formed by two rectangular boxes as the building units through the connectivity between Cd(II) and croconate and 4,4'-bpy ligands.