Two Co(II) coordination polymers, {[Co(ca)(bpe)(H 2 O)] • H 2 O} n (1) and [Co(ca)(bibp)] n (2) (H 2 ca = citraconic acid, bpe = 1,2-di(4pyridyl)ethylene, bibp = 4,4'-bis(imidazolyl)biphenyl) were prepared by hydrothermal reactions, and characterized by singlecrystal X-ray diffractions, elemental analysis, FT-IR, PXRD and TGA. Compound 1 shows a 2D grid layer containing Cocarboxylate chains. Compound 2 exhibits a three-dimensional metal-organic framework with the dia topology type and 6 6 topology symbol. Both compounds have high thermal stabilities and good phase purity. The photocatalytic reactions of two compounds were investigated under UV irradiation in the presence of H 2 O 2 , and the results show that both compounds are highly efficient photocatalysts for MB and RhB degradation, which may be used as potential materials for wastewater treatment.