Abstract: In this paper, the ability of photo generation of singlet oxygen as well as superoxide radical sensitized by metal phchalocyanines was evaluated. The results show that the ability of photo-generation of singlet oxygen is correlated with the triplet yield and tripet life time of the sen-sitizer The activity decreases in the order Zn>Ga>Cu>H₂>Al>Co. The ability of photogene-ration of superoxide radical depends not only on the triplet yield and triplet life time but also the excited energy and redox potential of the sensitizer. The ability decreases in the order Ga> Al>Cu>Zn. The fluorescence of metal phthalocyanine is quenched by tyrosine via electron transfer. Quenching of Ga phthalocyanine triplet state in deaerated solution by tyrosine giving rise to GaPc^- at 560nm. In oxygenated solution, subsequent electron transfer to oxygen occurs to give superoxide radical.

Key words: metal phthalocyanine, singlet oxygen, superoxide radical