Abstract: In recent years, there have been reports that many cobalt complexes are used by catalyst in different areas. The complexes were often used in CO2 copolymerization. General cobalt complexes used by catalyst in CO2 reaction contain salen(N,N’-bis(salicylidene)ethylenediamine) ligand. In this study, the novel cobalt complex containing salen ligand with pyridine was synthesized for developing new cobalt complex system. A new cobalt complex, Co(pyr2en)OAc, was synthesized by the reaction of pyr2en ligands (pyr2en =(N,N ‘-bis(pyridoxylideneiminato)ethylene) ) with Co(OAc)2. The complex was characterized by various spectroscopic methods such as infrared spectroscopy, HR-MS, single crystal X-ray crystallography. The complex is composed of a cobalt metal center, a tetradentate Schiff base ligand, an acetate ion and a DMSO molecules. By the square planar coordination of the ligands and an acetate anion and a DMSO, cobalt metal center has octahedral geometry. The synthesized cobalt complex was used in the cycloaddition reaction of CO2 to propylene oxide and the detailed study will be presented.