This paper introduces a novel concept utilizing thermally activated delayed fluorescence (TADF) molecules as photosensitizers, storage units, and signal transducers for solar thermal energy harvesting. Molecular composites based on the TADF core phenoxazine-triphenyltriazine (PXZ-TRZ) anchored with norbornadiene (NBD) were synthesized. Visible-light excitation triggers energy transfer to NBD's triplet state, leading to NBD → quadricyclane (QC) conversion, monitored through spectral changes. The small S1-T1 energy gap optimizes solar excitation wavelength. Modifying the molecule's triplet state energy below that of NBD reduces conversion efficiency. The reverse QC → NBD reaction, catalyzed at room temperature, releases stored chemical energy as heat, demonstrating excellent reversibility.
