Instead, if we can prepare a molecule containing multiple chromophores with a small core structure that has high rotational symmetry, we can expect to realize a situation where the triplet-exciton moves quickly between chromophores in the entire molecule by a pseudorotation caused by the dynamic Jahn-Teller effect on high symmetric molecule such as fullerenes. Thus it is expected that the unpaired orbitals in the triplet-exciton can be equivalent to be delocalized during the time scale of the bimolecular triplet-triplet encounter by the collision without lowering the triplet energy for improvement of 𝑘 ((# . To prove the concept of the above-mentioned strategy to improve 𝑘 ((# , we have employed a TTA-UC material of tri(9-anthryl)borane (TAB), which is a trimer-type fluorescent molecule that is expected to exhibit triplet-exciton hopping within the molecule with the addition of the photosensitizer, platinum 2,3,7,8,12,13,17,18-octaethylporphyrin (PtOEP). . The TTA-UC emission from TAB is investigated by time-resolved fluorescence measurement to determine 𝑘 ((# in the PtOEP/TAB system. The estimated 𝑘 ((# value is compared with that in PtOEP/DPA system, which is well known for its high UC quantum yield (𝛷 !" ≈ 24%), to verify the effect of exciton dynamics by the trimerization on 𝑘 ((# . Furthermore, the electronic structure of the triplet-exciton generated in TAB is investigated by using time-resolved electron paramagnetic resonance (TREPR), and it is clarified from a molecular point of view how the molecular structure and mobility contribute to the improvement of 𝑘 ((# .