By real-time vibrational spectroscopy using 6.8 fs pulses, real-time vibronic coupling in stair-like zinc chlorin aggregates was studied. Besides the observed fast excitonic relaxation, amplitudes of coherent molecular vibrations are found to be linearly dispersed from the resonant peak as a function of their own vibrational frequencies. In addition, the initial phases of the molecular vibrations exhibiting clear pi phase jump have been observed. All these results indicate that coherent vibrations in the artificial chlorosome intermediate energy exchange between the laser fields around the resonant peak and those separated from it by photon energy equal to the vibrational frequencies. (C) 2017 Elsevier B.V. All rights reserved.