Zinc(II) tetraphenylporphyrin (ZnTPP) moieties are covalently attached to amphiphilic sodium polysulfonates carrying about 60 mol % of lauryl (LA), 2-(naphthyl)methyl (Naph), or cyclododecyl (CD) groups. The ZnTPP moieties are compartmentalized within the hydrophobic clusters in aqueous solution, The charge transfer complexation of the compartmentalized ZnTPP moieties with methylviologen (MV2+) is completely suppressed, The electron transfer (ET) from the singlet excited state of the ZnTPP chromophore to MV2+ in the compartmentalized system is 2 orders of magnitude Blower than that in a reference copolymer system having no hydrophobic groups. The apparent second-order rate constants for the ET from the triplet, excited state of the ZnTPP chromophore to MV2+ are almost equal in all the polymer systems. The accumulation of ZnTPP+. was observed as a result of the compartmentalization. The Naph and CD groups are more effective in the accumulation of ZnTPP+. than is the LA group. ZnTPP+. persisted over st period of milliseconds in the terpolymer systems containing the Naph and CD groups.