Abstract: Liquid mixtures are used as the active medium in two-photon resonant four-wave mixing processes to achieve efficient nonlinear conversion of infrared laser frequencies. The resonant energy levels involved in these four-wave mixing processes are Raman-active vibrational modes of a molecular species which is one of the major constituents of the liquid mixture. Additional molecular and/or atomic constituents are added to the active molecular species to adjust the dispersion of the medium to optimize the nonlinear process. Diluents further may be used to fine-tune the two-photon resonance parameters to better match available infrared laser sources.