Performance metrics computed for the second-generation ML models. MAE is reported in eV for all models. The best R² and MAE for each property are in bold. The values are averaged over five-fold cross-validation models. The second-generation ML model results with and without ECFP2 are included.

Property	2nd gen without ECFP2		2nd gen with ECFP2
	R 2	MAE	R 2	MAE
HOMO	0.51 ± 0.011	0.351 ± 0.011	0.49 ± 0.009	0.354 ± 0.012
LUMO	064 ± 0.011	0.323 ± 0.007	0.69 ± 0.011	0.297 ± 0.004
H–L	0.39 ± 0.008	0.589 ± 0.015	0.42 ± 0.009	0.578 ± 0.011
VIE	0.75 ± 0.010	0.238 ± 0.006	0.78 ± 0.003	0.219 ± 0.001
AIE	0.76 ± 0.012	0.230 ± 0.003	0.80 ± 0.008	0.207 ± 0.003
CR1	0.26 ± 0.009	0.060 ± 0.001	0.17 ± 0.017	0.063 ± 0.001
CR2	0.29 ± 0.008	0.062 ± 0.001	0.34 ± 0.013	0.059 ± 0.001
HR	0.30 ± 0.013	0.118 ± 0.002	0.35 ± 0.012	0.110 ± 0.002
VEA	0.79 ± 0.012	0.233 ± 0.004	0.86 ± 0.003	0.186 ± 0.002
AEA	0.80 ± 0.003	0.224 ± 0.002	0.86 ± 0.001	0.176 ± 0.002
AR1	0.32 ± 0.007	0.059 ± 0.001	0.27 ± 0.037	0.062 ± 0.002
AR2	0.33 ± 0.023	0.053 ± 0.000	0.37 ± 0.015	0.051 ± 0.001
ER	0.38 ± 0.008	0.106 ± 0.001	0.41 ± 0.007	0.101 ± 0.002
S0S1	0.59 ± 0.016	0.313 ± 0.004	0.65 ± 0.010	0.282 ± 0.003
S0T1	0.62 ± 0.018	0.254 ± 0.005	0.75 ± 0.003	0.194 ± 0.003