There is mounting evidence that vibronic coupling and the associated quantum mechanical exchange of energy between excitonic and vibrational degrees of freedom could be at the heart of the counterintuitive long-lived coherence beating probed in ultrafast spectroscopy of photosynthetic complexes. Within this hypothesis, intramolecular vibrations influence excited-state dynamics through the formation of joint quantum states of excitonic and vibrational degrees of freedom. The exact influence such vibronic coupling on excited state dynamics is however not fully understood. In this talk I will discuss implications of coherent vibronic coupling for understanding truly quantum effects during excitation transfer and synchronisation processes in prototype light-harvesting systems.