This aggregate dependence of absorption energy positions and strengths is important for designing suitable aggregate lengths to control photo-physical processes, such as exciton dissociation and singlet fission. Therefore, we analyze the contributions of CT and LE states to the states corresponding to two absorption peaks. Fig. displays the ratio of CT/LE components in terms of aggregate lengths. In DPND6 aggregates, the LE-state components in the low-energy states are always larger than CT-state ones, whereas they are always smaller in the high-energy states. It is expected that absorption strengths of high-energy states cannot exceed those of lowenergy states, consistent with spectral calculations. However, in DPND aggregates with more than 4 monomers, the situation completely becomes inverse. In this case, the absorption at the high-energy state becomes stronger than that at the low-energy state. Since the more CT-state components appear in the low-energy states in DPND aggregates, the CT states may be easily generated by photo excitation to benefit charge separation and singlet fission. So far, we have only figured out the pure electronic-state properties of aggregates. To compare with experimental observations, one has to consider the vibrational effect, which may significantly justify the absorption spectra and dynamic processes. In subsequent section, we focus on the vibrationally resolved absorption spectra of aggregates.