We present our results on the investigation of ultrafast nonlinear optical properties including the time response of 2(3), 9(10), 16(17), 23(24) tetra tert-butyl phthalocyanine (pc1) and 2(3), 9(10), 16(17), 23(24) tetra tert-butyl Zinc phthalocyanine (pc2) studied using degenerate four-wave mixing technique at a wavelength of 800 nm with 100 fs pulses. We recorded large off-resonant second hyperpolarizabilities (γ) with estimated values of (4.27 ± 0.43) × 10-31 esu and (4.32 ± 0.43) × 10-31 esu for pc1 and pc2, respectively, with ultrafast nonlinear optical response in the femtosecond domain. We also estimated the figures of merit for photonic switching applications for both one-photon and three-photon loss mechanisms. The performance of these molecules vis-à-vis other molecules, in general, and phthalocyanines, in particular, is discussed. © 2008 Elsevier B.V. All rights reserved.