The recently proposed fragment localized molecular orbital(FLMO)based time-dependent density functional theory(TD-DFT)[J.Chem.Theory Comput.2011,7,3643] is employed to capture more than 300 low-lying excited states for three light-harvesting C—P—C60 triads composed of β-carotenoid polyene(C),diaryl-based porphyrin(P)and pyrrole-fullerene(C60).The simulated optical absorption spectra are not only in good agreement with experimental observations,but also enrich our understanding of structure-property relationships for these large light-harvesting molecules.Based on both top-down and bottom-up analyses of the excited states,we found the donor-to-acceptor transition probabilities will be increased(decreased)by parallel(perpendicular)conformation between the prophyrin ring and the link benzene ring.A maximum occupation method is further proposed for finding excited-state solutions of self-consistent field equation and is applied to long-range charge transfer states that cannot be described by TD-DFT with pure density functional.