Interactions of cationic tetrakis (N,N´,N´´,N´´´-tetramethyltetra-3,4-pyridinoporphyrazinatocobalt(II) (Co(tmtppa)) with synthetic polynucleotides, poly(A-T), poly(G-C) and calf thymus DNA have been characterized in 5 mM phosphate buffer, pH 7.2, by optical absorption and fluorescence spectroscopy. The appearance of hypochromicity effect and the red shift in UV-Vis spectrum of porphyrazine was ...