Comparing the EPR spectra between Figure and 4c in the T:P = 1:1 solvent, the linewidth of the EPR spectrum of the PtOEP/TAB system is about 3 mT (Figure ), while the linewidth of the EPR spectrum of the PtOEP/DPA system is about 30 mT (Figure ). This small linewidth for the TAB system should originate from the narrowing effect due to rotational motions of triplet-exciton of TAB faster than that of DPA in the presence of the magnetic field, because the ZFS couplings were similar in the viscous media. Typically, molecules with small molecular radii are expected to rotate quickly, leading to more prominent motional narrowing effects. The quick rotation of triplet-excitons on the TAB would be due to the pseudo-rotation rather than molecular rotation. Therefore, we hypothesize that the intramolecular triplet-exciton hopping occurs within TAB and thus contributes to the enhanced 𝑘 ((# . On the other hand, we surmise that the 30 mT width in Figure is caused by the molecular rotation diffusion in 3 DPA* because no exciton hopping is expected at the dilute DPA concentration in the fluid. The spin density distribution of the triplet-exciton of TAB is shown in Figure . We found that the distribution of triplet-exciton in TAB molecule is localized on two anthracene moieties. There are similar reported cases of the spin distributions in the two moieties in systems where three chromophores are linked by a central atom. The localized spin density is a consequence of the involvement of the symmetry breaking CT character in Figure , resulting in distortions from the C3 symmetry. This CT contributes to the high T1 level in TAB (Figure ) because the CT may avoid the exchange stabilization by the overlap between the unpaired orbitals 56 with respect to the stabilized triplet in pentacene due to the delocalized unpaired orbital distributions with possessing the large orbital overlap.