Push-pull charge-transfer organic molecules exhibit large second-order nonlinear optical nonlinearity , and have been used to manufacture efficient photonic devices .We study a series of CT molecules by using the two-photon scattering method with a tunable femto-second pulsed-laser to obtain the value of the molecular first hyperpolarizability (£]) .We discuss the relationship between the£]value and chemical structure , and compare the£]values with the two-level model prediction for several incident laser excitation wavelength.