Supporting Information. Materials and experimental methods, DFT calculation result for TAB, Calculation method of initial triplet concentration of TTA emitters, Method of spectral analysis, discussion about the temperature dependence of D value in DPA, additional TREPR data and the results of spectral analysis at various temperatures, further consideration of the validity of intramolecular hopping rate constant, result of viscosity measurement. This material is available free of charge via the Internet at .