Simple mixing of manganese(III) complex of alpha,alpha,alpha,alpha-tetrakis(o-aminophenyl)porphyrin (Mn-1) with metal oxides afforded monomeric adsorption of Mn-1 on the metal oxide, where the porphyrin plane faces parallel to the solid surface. The styrene conversion with iodosylbenzene catalyzed by Mn-1 was greatly improved by immobilization on basic metal oxides, not only due to high dispersion but also due to the interactions with the support.