The title compound [Co(5-NH2-bdc)(4,4'-dpdo)(H2O)](n) 1 (5-NH2-bdc = 5-aminoisopthalic acid, 4,4'-dpdo = 4,4'-bipyridrl-NN'-dioxide) crystallizes in triclinic, space group P (1) over bar with a = 4.999(1), b = 10.072(2), c = 13.028(3) angstrom, alpha = 107.72(3), beta = 92.58(3), gamma = 98.11(3)degrees, V = 615.9(3) angstrom(3), F(000) = 356, R-int = 0.0186, Z = 2, R = 0.0333, wR = 0.0721, S = 1.032 and (Delta/sigma)(max) = 0.001. In the molecule of 1, the Co(II) cation is coordinated by three O-atoms of two 5-NH2-bdc ligands, one N-atom of another 5-NH2-bdc ligand, one O-atom of 4,4'-dpdo and one terminal O-atom. of water molecule. The molecules construct a 2-D network through bridging 5-NH2-bdc and 4,4'-dpdo ligands, and further form a 3-D network through N-H center dot center dot center dot O and O-H center dot center dot center dot O hydrogen bonds. The network topology of 1 can be simplified as a rare 2D (3,6)-connected (4(2)6(3)8(1)) net.