In contrast to the results for the S 1 energy, the influence of solvent on the S 1 -T 1 gap is much smaller, less than 0.1 eV. Still, lowering the S 1 -T 1 gap facilities the reverse inter-system crossing process, thus enhancing TADF. Moreover, the solvent effect shown is in contrast to previous work, 15 where the environment showed no impact on the S 1 -T 1 energy gap. This difference is assigned to an improved description of the excited state structure and increased CT character of the excited state in the present work.