For the reference p𝐾 𝑎 in water (the first term in Eqn. ( )), we utilized DFT to determine the p𝐾 𝑎 of the ionizable group in the emitter and the acid species in both the ground and first excited singlet states using Eqn. (10) shown below. For the ground state, all geometries, whether in the gas or solvent phase, were optimized using the CAM-B3LYP /Def2-SVP level of theory. TD-CAM-B3LYP was employed for optimizing the first excited state and calculating the emission energies of the first three singlet excited states (nstates=3). The SMD solvation model was applied for solvent phase calculations, and the GD3BJ method was used for dispersion correction. Electronic and thermal energies, calculated at 298.15 K, were determined using standard statistical thermodynamic methods, incorporating unscaled frequencies and the ideal gas, rigid rotor, and harmonic oscillator approximations. The Gaussian 16 software suite was used to carry out all electronic structure calculations. The charges of the chromophore in the ground and excited state used in PDLD and QCFF/PI calculations were obtained used the DFT method described above. From the resulting charges, we generated the restrained electrostatic potential (RESP)-fitted charges using AmberTools17. Using the thermodynamic cycle (see Fig. in the Supporting Information), the free energy of deprotonation (∆𝐺 𝑎𝑞 ) for the acid species in solution, given by, 𝐻𝐴 + 𝐻 2 𝑂 ⇋ 𝐻 3 𝑂 + + 𝐴 -can be calculated using: