Quantum chemical calculations support the color tuning mechanism based on aggregation-induced TSCT. In ground state, while the LUMO is located on the NDI core at a constant level, the HOMO levels increase proportionally with the -conjugation degree of the polycyclic aromatic groups, resulting in controlled energy bandgaps. In excited states, CT transitions generated redshifted emission with a D-A spatial proximity within ~7 Å, which was influenced by the donor group concentration in polymers. Finally, we demonstrated the potential of this universal polymer platform for high-contrast photochromic information encryption.