While there are a few cases not predicted to be SCO complexes by one or more of these three functionals, the DGH-L values are still typically within ca. 2 kcal/mol of the defined range of DGH-L between -5.5 and 5.5 kcal/mol (Figures and and Supporting Information Tables , Text S1, and Figures ). For example, two complexes with refcodes QAXQIR 183 and YAGYUB 157 are not predicted to be SCO complexes by all three functionals (Figures and and Supporting Information Table and Figure ). However, crystal structure analysis combined with results from high-resolution powder-diffraction data demonstrate gradual and complete SCO behavior of YAGYUB 157 . QAXQIR 183 is also experimentally determined to be an SCO complex based on analysis of X-ray crystal structures, Mössbauer studies, UV/Vis, and NMR spectroscopy data. While SCO behavior is predicted by all three functionals for a majority of the complexes (68 out of 95 systems), the predicted DGH-L values vary quite a bit between these functionals (Supporting Information Figure and Table ). For example, while a complex (REFCODE: IBUVUW 184 ) is predicted to show SCO behavior by both modB3LYP (aHF = 0.10) and TPSSh, they differ significantly in the DGH-L value (i.e., -0.6 kcal/mol vs 4.1 kcal/mol, Supporting Information Figures S25 and S27 and Table ). Similarly, OSABOB 179 , which was an outlier for TPSSh, is more consistently predicted as an SCO from both modB3LYP (aHF = 0.10) and M06-L, but they have a large (i.e., 6 kcal/mol) difference in DGH-L values (2.1 kcal/mol vs -4.2 kcal/mol; Supporting Information Figures and and Table ). Thus, even among top-performing functionals that predict a large number of complexes to have SCO behavior, quantitative SCO free energies may differ, and there remain outliers that are experimentally validated as SCO but that cannot be captured in a one-size-fits-all DFA choice.