The hydrothermal reaction of cobalt (Ⅱ) chloride hexahydrate with 2, 5-pyridinedicarboxylic acid and 4, 4'-dipyridyl gave a mononuclear Co(Ⅱ) compound, the empirical formula of [Co(C7H4NO4)2(H2O)2]. The crystalline product have been characterized by elemental analysis, FTIR spectroscopy, and X-ray diffraction. The title compound, the coordination sphere of the Co metal, is distorted octahedral coordination with an approximate C2 symmetry. It is defined by two pyridine N atom, two carboxylato O atoms and two water O atoms in cis positions. The crystal structure is stabilized by intermolecular O-H⋅⋅⋅O hydrogen bonds between carboxy and water O atoms.