In this paper time-delayed four-wave mixing with incoherent light is applied for the study of vibratlonal dephasing processes of some dye molecules in excited electronic states. The information on subpicosecond dephasing time in absorption band of oxagine in PMMA and in solution, and in absorption edge of cresyl violet in PMMA has been obtained. A detailed physical interpretation of the observed dephasing time is given on the basis of our multi-level theory of time-delayed four-wave mixing with incoherent light.