The effect of manganese protoporphyrin, manganese halogenated porphyrins, polyethylene glycol (PEG)-linked manganese porphyrin and PEG-linked manganese halogenated porphyrins (Scheme 1), on the decoloration rates of C.I. Solvent Yellow 14 by m-chloroperbenzoic acid (mCPBA) at 25°C in non-aqueous solvent was examined. The decoloration rate of C.I. Solvent Yellow 14 by mCPBA was accelerated due to the presence of manganese porphyrin derivatives, depending on the structures of porphyrin derivatives. Interestingly, the decoloration rate decreased due to the presence of ligands such as imidazole, in comparison to the rate catalyzed by the manganese porphyrins in aqueous solution.