New hydrophilic immobilized photosensitizers (heterogeneous phase) were synthesized that overcome some disadvantages of the use of homogeneous phase sensitizers for detoxification and disinfection of water. The chosen sensitizers, based on porphyrin moieties, were bound on poly(methyl methacrylate) (PMMA). The measured production rate of singlet oxygen is significantly higher than that of the well-known rose bengal immobilized on Merrifield polymer. The sensitive polymer can be used for detoxification and disinfection of polluted water.