Measurements on the third order optical nonlinearities of the conjugated polymeric cast film of PPQ (polyphenylquinoxalines) were performed at 532 nm wavelength using a frequency doubled mode-locked Nd:YAG laser with 10 Hz repetition rate. Strong two-photon absorption coefficient β=0.59 cm/MW was obtained for PPQ. The measured nonlinear refractive index coefficient n2≈9.5×10-10 esu, was in agreement with the previously reported value. It was attributed to a purely electronic response for the optical nonlinearity, and the figure of merit of PPQ was assessed.