The use of four‐wave mixing techniques in femtosecond time‐resolved spectroscopy has considerable advantages. Due to the many degrees of freedom offered e.g. by coherent anti‐Stokes Raman scattering
(CARS), the dynamics even of complex systems can be analyzed in detail. Using pulse shaping techniques in combination with a self‐learning loop approach, molecular mode excitation can be controlled very efficiently in a multi‐photon excitation process. Results obtained from the optimal control of CARS on β‐carotene are discussed.