Abstract: The single-shot coherent anti-Stokes Raman scattering spectra of liquid N, N-Dimethylformamide (DMF) when mixed with nitrotetraphenylporphin (PNNNN) in different concentrations have been obtained experimentally. The results show that the additive PNNNN has enhanced the intensity of the CARS resonance line 865cm-1 of DMF relative to other CARS lines of DMF. This phenomenon is interpreted as the mutual effect between different molecules by an analysis of third -order susceptibility.