In the area of metal-organic porous materials, supramolecular metal-organic frameworks (SMOFs) constitute a blooming alternative. Their examples are still relatively scarce when compared to MOFs (metal-organic frameworks), and as far as we are aware there is not any study dealing with the crystallographic location of adsorbate molecules within the porous structure. The materials selected for the current study are featured by being especially selective towards CO2 molecules. Thus, the current work aims to get deeper insight into the adsorptive behaviour of these materials since evidences on the mechanistic and pore occupation under different pressure and temperature conditions would enlighten the adsorption mechanistic of these materials and explain this remarkable adsorption selectivity.