Intensities and decay rates of delayed luminescence (DL) initiated by a pulse of N2 laser or CO2 laser were employed to probe collisional relaxation of complex molecules (benzophenone -- C13H10O, acetophenone -- C8H8O, anthraquinone -- C14H8O2) diluted with bath gases: Ar, C2H4, SF6, C5H12, CCl4. It was shown that time resolution about 10-8 sec permit one to divide the V-V and V-T processes for such large and complex molecules, the relaxation occurs in two stages. Upper levels relax through V-V transfer, which completes after several collisions. The collisional efficiencies of V-V process had the values typical for supercollision. The average energies transferred per collision, <(Delta) E>, well correlate with predictions of the simple ergodic collision theory of intermolecular energy transfer. The majority of energy transfer collisions involve V-T/R transfer of relatively small energies. The CO2 laser excitation method to initiate the DL allowed to obtain only V-T CET quantities because of lower time resolution.