By adopting mixed-ligand strategy,two Co(Ⅱ) coordination polymers,[Co(phda)(itmb)(H2O)2]n (1) and[Co(phda)(Hpytz)]n (2) (H2phda =1,2-phenylenediacetate,itmb =1-(imidazo-1-ly)-4-(l,2,4-triazol-1-yl methyl) benzene and Hpytz =3,5-di(4-pyridyl)-1,2,4-triazolate),were hydrothermally synthesized and then characterized by elemental analysis,IR spectroscopy,thermogravimetric analysis (TGA),powder X-ray diffraction (PXRD) and single-crystal X-ray diffraction.The single-crystal X-ray diffraction reveals that two complexes feature carboxylato-bridged binuclear subunits extended further by the nitrogen-rich coligands to form different structures.Complex 1 containing phda-bridged binuclear cobalt is developed by itmb coligand to 1 D double-stranded chain,whereas complex 2 exhibits 2D open bilayers,which result from the ribbon-like carboxylate chains pillared Hpytz coligands.In addition,the magnetic susceptibilities of both compounds were measured over the temperature range of 3～300 K,and the data were analyzed well using MagSaki software.The best fitting parameters were κ =0.98,λ =-100 cm1,△ =588 cm-1 and J =0.6 cm-1 for complex 1 and κ =0.86,λ =-110 cm-1,△ =756.8 cm-1 and J =-1.25 cm-1 for complex 2.The results indicate the existence of weaker ferromagnetic interaction for complex 1 and antiferromagnetic interaction for complex 2 between the metal centers in the dinuclear metal units.