Novel polymeric photosensitizers for singlet oxygen production in water are described. The polymers contain rose bengal (4,5,6,7-tetrachloro-2',4',5',7'tetraiodo-fluorescein) chromophores covalently attached to the polymer chain. The quantum yields of singlet oxygen formation and photooxidation of phenol in water have been determined. The methods of separation of photosensitizer from the reactants after completion of reaction have been established.