Acidic and basic properties of β -substituted derivatives of tetraphenylporphyrin are studied. First and second stage ionization constants for ligands investigated are reported. Acidic properties of porphyrins are in good agreement with classical theories about influence of substituent’s nature and geometrical structure of macrocycle on their physical and chemical parameters. It is found that porphyrins have catalytic activity in heterogeneous oxidation of N,N-diethylcarbamodithioate.