Based on above electronic-state absorption spectra, we calculate the vibrationally resolved absorption spectra of aggregates including 6 to 10 monomers in DPND6 and 6 to 18 monomers in DPND for the purpose of comparison. The calculated spectra as well as experimental observations are shown in Fig. , in which the calculated spectra for DPND6 and DPND aggregates are redshifted by 0.016 eV and blue-shifted by 0.12 eV, respectively. It is noted that the high energy region of the spectra is not included in the present calculations since we only account for few lowest-energy intramolecular LE states and CT states, furthermore the experimental spectra of DPND6 aggregate in high energy region is lack.