4,6-bis[(1E)-N-(2-hydroxyethyl) ethanimidoyl] benzene-1,3-diol) Cobalt and (4,6-bis [(1E)-N-benzylethanimidoyl] benzene-1,3-diol) Cobalt complexes were successfully supported on Al2O3. Furthermore, the catalytic effectiveness of each were evaluated in the process of decomposition of hydrogen peroxide (H2O2). It's interesting to note that the loading Co-complexes on Al2O3 catalyst resulted in a notable advancement in the catalytic efficiencies compared with single Al2O3catalysts. However, the influence of the concentration of Co-complexes were studied to get optimum amount. The catalysts were then examined using high-resolution transmission electron microscopy (HR-TEM), N2 adsorption-desorption analysis, and X-ray diffraction (XRD). Results denoted that 0.015 Co-complexes / Al2O3 have the highest catalytic activity. The effect of temperature on the catalytic decomposition of H2O2 has been investigated it was found that as the temperature increases the catalytic activity enhanced. Ultimately, the 0.015 Co-complex / Al2O3 catalyst showed greater stability throughout the H2O2 decomposition process and is recyclable several times.