The complexation of the neg. charged. Zn tetraphenylporphyrin sulfonate with the pos. charged viologens was investigated by absorption and emission spectroscopy, resp. The complexation constant increases with the hydrophobicity of the viologen used. In the sensitized photoredn. of Me viologen the average rate of production of Me viologen radical cation for the 1st 15 min increased with the initial concentration of Me viologen, contrary to the initial rate reported by I. Okura et al. (1983, l985), which increases to a max. and then decreases with the increase of the initial Me viologen concentration

Key words: PORPHINE P, SODIUM COMPOUNDS, VIOLOGENS, WATER, PHOTOOXIDATION, ZINC COMPLEX, CONCENTRATION, BENZENE P, SULFONATE, ASSOCIATION