The two underlying distributions in the band gap data can be better understood by separating the computed values based on whether the material has closed-shell or open-shell character, the latter of which is associated with lower band gaps on average (Figure ). When including 10% HF exchange with HSE06 * , the degree of overlap between the closed-shell and open-shell band gap distributions is partway between that of PBE and HSE06 (Figure ), which illustrates the strong dependence of the trends on the fraction of HF exchange. Taking the hybrid-quality calculations as the more accurate reference point, these findings suggest that the PBE functional exhibits severe quantitative and qualitative shortcomings when applied to a wide range of MOF structures and that these shortcomings go beyond a simple underprediction of the band gap. Although HLE17 increases the median band gap of the dataset compared to PBE and decreases the number of structures with a predicted band gap in the low-energy subset, it retains the bimodal nature of the band gap distribution. Nonetheless, HLE17 does significantly increase the band gaps of the closedshell frameworks, and the distribution of band gaps for the closed-shell MOFs is similar to that of HSE06 * . By directly comparing the predicted band gaps for the PBE, HSE06 * , and HSE06 calculations, we find that there is a correlation between the median band gap and the fraction of HF exchange (Figure ), at least within the range of 0-25% HF exchange considered in this work. Assuming linear behavior in this region, it can be concluded that the median band gap across the dataset changes by ~0.05 eV per percent of HF exchange for the closed-shell frameworks and ~0.10 eV per percent of HF exchange for the open-shell frameworks, although we emphasize that these statistics are specific to the QMOF Database and may differ for other datasets of MOFs. Collectively, these results have significant implications for computational screening studies of MOFs and coordination polymers, as the use of GGA functionals like PBE may lead to incorrect qualitative comparisons between the band gaps of different materials if some have closed-shell character and others have open-shell character.