The initial structures of DPND6 and DPND monomers are extracted from the crystal structures and then they are optimized by using the density functional theory (DFT) with the exchangecorrelation (XC) functional B3LYP. The basis set of def2-TZVP is adopted and the Grimme3 dispersion correction to DFT is included. The vertical excitation energies and the corresponding oscillator strengths are calculated by time-dependent DFT (TD-DFT) with the tuned long-rangecorrected XC functional LC-ωPBE with ω = 0.157 for DPND6 and ω = 0.193 for DPND and the basis set of 6-311G(d,p). The vibrational frequency analysis for the ground state of DPND6 and DPND monomer either in DCM solution or in crystal environment are carried out at the level of B3LYP/def2-TZVP and all the vibrational frequencies are scaled by a scaling factor of 0.959 accounting for the anharmonicity effect. All the vibrational modes (a total of 180 for DPND6 and 72 for DPND monomer) are involved in the simulations. All the calculations are carried out within Gaussian 16 program package. The solvent and crystal environment are incorporated by using the solvent model of density (SMD) and the dielectric constants for DPND6 and DPND crystals are set to be 4.6 and 3.4, respectively. To construct the electronic Hamiltonian of aggregates, we carry out the diabatization processes of DPND6 and DPND hexamers. The total number of 180 low-lying adiabatic states are included.