1 LED and 1 CT mixed emission systems of DAAPC/2,8-PPT and DAAPC/4,6-PPT showed a clear blueshift in the spectral onset at higher temperatures. Since the TL intensity at low temperatures is stronger than that at high temperatures for these systems, this blue shift can be attributed to thermal upconversion from CT to 1 LED. DAAPC/2-PPT did not show significant spectral onset variation, but efficient 1 CT to LED upconversion was revealed by quantum chemistry simulation (Figs. , Supplementary Information 4.12.2).