Since the supervised ML model takes in molecular structure and excited state data, we must obtain excited state data for all molecules. xTB-sTDA data was all independently generated. A 3D structure was first intialized using OpenBabel's gen3d function for a short conformer search and preliminary geometry optimization. Full ground-state optimization was conducted with GFN2-xTB with the tight threshold and a benzene generalized-Born surface-area (GBSA) solvation model to mimic a non-polar environment. xtb4stda 55 was then used to prepare the wavefunctions output by xTB for sTDA. Finally, sTDA was used to calculate excited-state properties, using an energy threshold of 10 eV. The -t flag was used for triplet excited state calculations. For TD-DFT data, database values were used where available. PCQC had S 1 TD-DFT data, but T 1 data was independently generated. MOPSSAM had S 1 TD-DFT data for the 143 calibration set, but not for the 1000 sampled molecules, so this was independently generated (see Figure for a comparison of MOPSSAM 143 S 1 data vs. S 1 data generated with our workflow, showing virtually identical results). T 1 TD-DFT data was also independently generated. Both INDT and VerdeDB had S 1 and T 1 TD-DFT data available. However, VerdeDB used the M06 functional for calculations, so these molecules were re-calculated with B3LYP.