A new supported dinuclear Mn(II) complex catalyst has been synthesized through the tethering of a dinuclear chelating ligand, 1,4,7,10,13,16,19,22-octaazacyclotetracosane (N-BISDIEN), to the surface of mesoporous silica. The solid material obtained was characterized by elemental analyzes and ESR techniques. The potentiometric method was employed to investigate the stability of dimanganese(II) species. Catalytic experiments indicate that the prepared material is efficient in disproportionation of H 2 O 2 in aqueous solution.