For the copper complex of pyrazinoporphyrazine AzaPhcCu(C(CH_(3))_(3))_(8) in CH_(2)Cl_(2), we use nanosecond pulses to measure its third-order nonlinear optic effects at 532 nm. The results show that its effective third-order nonlinear refractive index n_(2)~(eff) (-7.85×10~(-10) esu) is larger than that of the AzaPhcCu(C_(12)H_(25))_(4) and the CuPc(OC_(5)H_(11))_(8). The reverse saturable absorption (RSA) of AzaPhcCu-(C(CH_(3))_(3))_(8) is demonstrated by the ratio of effective excited state to ground state absorption cross sections. The observed intersystem crossing lifetime τ_(isc) of AzaPhcCu(C(CH_(3))_(3))_(8) (～15 ns) and AzaPhcCu(C_(12)H_(25))_(4) (～45 ns) are longer than that of CuPc(OC_(5)H_(11))_(8) (～5.0 ns). The aza-substituents are suggested to form a S_(1)(n,π~(*)) state as their lowest excited singlet-states, and their radiationless intersystem crossing rates (1/τ_(isc)) are discussed with the spin-orbit coupling and the vibronic coupling effects between S_(1) and T_(1) states.
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