Soluble vanadyl phthalocyanines with different substituents and substituted in different position were synthesized. 10^-^3^1 esu and 10^-^1^0~10^-^9 esu order of magnitude of off-resonant third-order hyperpolarizability <γ> and X^(^3^) values for them were measured, respectively, by degerate four-wave mixing. It is found that the <γ> value is depended on the nature of the substituents. The stronger the electron-donating ability of substituent, the larger the <γ> value. However, the substituting position has only little effect on the <γ> value.

Key words: OPTICAL PROPERTIES, SUBSTITUENT EFFECT, OXYGEN COMPOUNDS, VANADIUM COMPOUNDS, PHTHALOCYANIN (=PHTHALOCYANINE)