Oxygenation constants and thermodynamic parameters DHo and DSo of cobalt (II) complexes with bis-(furaldehyde) Schiff bases (1, 2, 3, 4)were obtained by mearsuring saturated dioxygen uptake of these complexes in pyridine at different temperature. These complexes could activate molecular oxygen and were used as catalysts in cyclohexene oxidation. The influence of ligand structure on the dioxygen affinity and catalytic activity of the complexes were discussed. These complexes were obtained by mearsuring saturated dioxygen uptake of these complexes in pyridine at different temperature. These complexes could not react with these complexes in bis- (furaldehyde) Schiff bases (1, 2, 3, 4) activated molecular oxygen and were used as catalysts in cyclohexene oxidation. The influence of ligand structure on the dioxygen affinity and catalytic activity of the complexes were discussed.