We now aimed to test our trained ML models on SCO complexes from the SCO-95 data set where experimental T1/2 values were not available. To validate our method of estimation, we compared 40 estimated T1/2 values as an average of low-and high-temperatures (low-T and high-T) of crystallization and found excellent agreement for this set of 74 SCO complexes, with a high Pearson's r of 0.93 and Spearman's r of 0.89 (Supporting Information Figure ). Thus, over the remaining set of 19 SCO complexes from the SCO-95 data set where experimental T1/2 values are not reported, we were able to obtain estimated T1/2 values for 18 complexes. We could not obtain estimated T1/2 for one complex (refcode: JOTQAN 132 ) because the high-temperature of crystallization for this complex was not reported. These 18 SCO complexes all have Fe-N bonds and ligands that contain hydrogen, carbon, and nitrogen, with some complexes additionally containing boron, oxygen, sulfur, and bromine (Supporting Information Figures ). Of these and Supporting Information Table ). This performance is roughly ). We observe that the RF-RFA RF model performs only slightly better than the RF model, and both these models outperform the RF-RFA KRR model (Figure and Supporting Information Table ). The predictions from the KRR model show no correlation with estimated T1/2 values and have a large MAE of 104 K (Figure and Supporting Information Table ). Consistent with prior observations, all ML models trained on the set of 61 SCO complexes, which includes an outlier with a large T1/2 value of 445 K, perform worse on the blind set of 18 SCO complexes (Supporting Information Table and Figure ).