In this study, we employed M I M4Cl3(bta)6 clusters as a model for the SBU of MFU-4l frameworks. It is noteworthy that this cluster can be found in several analogous frameworks, as shown in Figure . Assuming that the H2-M I binding interactions are not affected significantly by the crystal environment and the nature of the triazolate ligand, the volumetric usable capacity for the analogous frameworks would be proportional to the density of the M I sites. Assuming the same degree of incorporation of M I atoms into Kuratowski-type clusters for the frameworks considered, based on the density of SBUs we can expect that the volumetric usable capacity would increase in the following row CFA-19 < MFU-4l < CFA-1 < MFU-4 with relative cluster density of 0.57, 1.00, 1.40, and 2.93, respectively (Table ). This highlights the significance of understanding the properties of these SBUs within the cluster model to develop MOFs for hydrogen storage. However, we acknowledge a limitation inherent to our approach: our analysis focuses on cluster models rather than periodic systems, omitting the influence of the periodic environment. As a promising direction for future research, one could explore how the flexibility of linkers and the periodic environment of a particular MOF might influence the hydrogen adsorption properties at the open metal sites. These investigations could be done either through synthetic methods or by employing periodic calculations to provide deeper insights into the structural factors that govern H2 adsorption, thereby enhancing the functional design of new materials for hydrogen storage.