beta-Tetrabromo-meso-tetrakis(4-methoxyphenyl)porphyrin, H-2 T(4-OCH3 P)PBr4, was synthesized and characterized by UV-V-is and H-1 NMR spectroscopy. Oxidation of alkanes and olefins with tetra-n-butylammonium peroxymonosulfate (n-Bu-4 NHSO5) was studied in the presence of MnT(4-OCH3 P)PBr4 (OAc) and MnTPPPBr4 (OAc) (TPP = meso-tetraphenylporphyrin). While significance differences were observed between the catalytic activities of the title complexes in the oxidation of alkanes, the 2 manganese porphyrins showed comparable activities in oxidation of most of the olefins used. However, the latter showed greater catalytic performance in the oxidation of the hydrocarbons. Moreover, the oxidative degradation of the former (60%) was greater than that of the latter (45%) in the oxidation of cyclooctene.