Crystal structure of catena-poly[[di-aqua-cobalt(II)]-bis-[μ-5-(4-carb-oxy-ylato-phenyl)picolinato]-κ(3) N,O (2):O (5);κ(3) O (5):N,O (2)-[di-aqua-cobalt(II)]-μ-1-[4-(1H-imidazol-1-yl)phen-yl]-1H-imidazole-κ(2) N (3):N (3')].

The asymmetric unit of the title polymeric Co(II) complex, [Co2(C13H7NO4)2(C12H10N4)(H2O)4] n , contains a Co(II) cation, a 5-(4-carboxyl-atophen-yl)picolinate dianion, two coordination water mol-ecules and half of 1-[4-(1H-imidazol-1-yl)phen-yl]-1H-imidazole ligand. The Co(II) cation is coordinated by two picolinate dianions, two water mol-ecules and one 1-[4-(1H-imidazol-1-yl)phen-yl]-1H-imidazole mol-ecule in a distorted N2O4 octa-hedral coordination geometry. The two picolinate dianions are related by an inversion centre and link two Co(II) cations, forming a binuclear unit, which is further bridged by the imidazole mol-ecules, located about an inversion centre, into the polymeric chain propagating along the [-1-11] direction. In the crystal, the three-dimensional supra-molecular architecture is constructed by O-H⋯O hydrogen bonds between the coordinating water mol-ecules and the non-coordinating carboxyl-ate O atoms of adjacent polymeric chains.