( 1.4a2.dev723). In this workflow, we first carried out basis set projection from LACVP* to def2-SVP 145 for functionals with different HF exchange fractions, followed by single-point energy calculations with def2-SVP. The converged def2-SVP wavefunction molecular orbital coefficients from TeraChem single-point energy calculations were used as an initial guess for Psi4 def2-TZVP SCF calculations with varying HF exchange fractions in the functional. Self-consistent singlepoint energies for 22 DFAs were obtained by using the converged Psi4 B3LYP/def2-TZVP wavefunction as an initial guess using the recommended grid size 147,148 with 99 radial points and 590 spherical points. These calculations were run with a maximum of 100 SCF iterations to reach SCF convergence with convergence thresholds of 3.0 × 10 -5 Ha for both energy and density, and all calculations were successful. Single points with Psi4 were obtained in the gas phase due to incompatibility of the previously developed workflow 121 in Psi4 with implicit solvent models. We then computed spin splitting energies between HS and LS states using both electronic energies (DEH-L) as well as Gibbs free energies (DGH-L). Corrections to electronic energies to obtain Gibbs free energies were all obtained from modB3LYP (aHF = 0.10)/LACVP* thermodynamic corrections at T = 300 K. Differences were observed between DEH-L electronic energies obtained with LACVP* and def2-TZVP basis sets, which in turn affected the predictions of SCO complexes (Supporting Information Figure ). Thus, DEH-L values for these 23 DFAs and modified B3LYP (modB3LYP) with varying HF exchange fractions were obtained with the larger def2-TZVP basis set. Nevertheless, we used the smaller basis set for the thermodynamic corrections in combination with def2-TZVP electronic energies due to the prohibitive computational cost of carrying out frequency calculations with the larger def2-TZVP basis set. Predictions of the spin-crossover temperature, T1/2, are obtained by identifying the temperature at which the HS and LS states have the same Gibbs free energies, which results in the expression, T1/2 = DHH-L/DSH-L. Here, the entropic contributions are assumed to be fairly constant with temperature and are evaluated from our T = 300 K thermodynamic corrections.