Supported tetra(-4-pyridyl)porphyrinato-manganese(III)[Mn I I I (TPyP)] + and -tin(IV)[Sn I V (TPyP)] 2 + have been prepared. The solid support was iodonated poly(siloxane) surface prepared by condensation reactions of (EtO) 4 Si with (MeO) 3 Si(CH 2 ) 3 I. The supported metalloporphyrins were employed as catalysts for the oxidation reactions of l-octene and of cyclohexene. NaBH 4 was used to reduce [Mn I I I (TPyP)] + and [Sn I V (TPyP)] 2 + back to their catalytically active Mn I I and Sn I I 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 I I I (TPyP)] + catalysed l-octene oxidation as well, whereas the supported [Sn I V (TPyP)] 2 + was inactive for the oxidation of l-octene.