Abstract Supported tetra(-4-pyridyl)porphyrinato-manganese(III) [Mn III(TPyP)] + and -tin(IV) [Sn IV(TPyP)] 2+ have been prepared. The solid support was iodonated poly(siloxane) surface prepared by condensation reactions of (EtO) 4Si with (MeO) 3Si(CH 2) 3I. The supported metalloporphyrins were employed as catalysts for the oxidation reactions of 1-octene and of cyclohexene. NaBH 4 was used to reduce [Mn III(TPyP)] + and [Sn IV(TPyP)] 2+ back to their catalytically active Mn II and Sn II forms, respectively. Contrary to their homogeneous counterparts, both of the supported metalloporphyrins catalysed the cyclohexene oxidation reaction to yield only 2-cyclohexen-1-one with no other products over a reaction time of 10 h. In addition to cyclohexene oxidation, the supported [Mn III(TPyP)] + catalysed 1-octene oxidation as well, whereas the supported [Sn IV(TPyP)] 2+ was inactive for the oxidation of 1-octene.