To verify these assignments, we measured the phosphorescence spectra of Cz-Ph and PTZSO 2 at 77 K (Figures and). It was found that the dual RTP emission bands of Cz-C-PTZSO 2 match the phosphorescence of the Cz-Ph monomer (T 2 ) and the PTZSO 2 aggregate (T 1 ). Notably, the calculations predicted that T 1 and T 2 of Cz-C-PTZSO 2 are localized on Cz-Ph and PTZSO 2 (Figure ), respectively. However, the sample includes both monomers and aggregates, so experimentally we assign the higher-energy T 2 emission to localized Cz-Ph donor emission of Cz-C-PTZSO 2 while the lower-energy T 1 emission is associated with LE emission on the PTZSO 2 acceptor of the aggregate of Cz-C-PTZSO 2 . The excitonic splitting that is present in the aggregates explains the divergence between the calculations and experiments. Therefore, it indicates multiple intermolecular interactions exist in the PTZSO 2 fragment of Cz-C-PTZSO 2 (vide infra).