On the basis of our previous work , we construct here an excitonic model to study the role of vibrational coherences and the intermediate CT state in the SF process. To build this unified model, we use prototypical materials, pentacene and tetracene single crystals. The functional role of the CT state is examined by adding the CT state with the vibronic coupling to the effective modes in the modelling. We also consider the impact of vibrational coherences in the process of the PSF by including the vibrational modes coupling to the electronic excited states. The energy difference of triplet-pair state and the CT state in pentacene and tetracene is considered by the different energy gap between S 1 , T 1 T 1 and S 1 , CT states. With the constructed model, we perform the calculations of population dynamics by quantum master equation. By this, we uncover the role of CT state during the process of PSF. With the different PSF lifetimes, the role of the CT state is different in pentacene and tetracene single crystals. In pentacene, the strong interacted vibrational modes (intramolecular/intermolecular modes) form the effective channel for the deactivation of population from the singlet S 1 to T 1 T 1 state, which drives the population transfer in the timescale of 100 fs. The impact of CT state is limited during the short timescale. In contrast, the CT state plays a role in a relatively slower process of the PSF in tetracene with the mediation of population by vibronic coherences. The unified model allows us to systematically study the population dynamics and uncover the role of quantum coherent effect in the process of the PSF. The uncovered principles in this work could help the designing of new generation of artificial photovoltaic devices.