Hydrogen adsorption measurements and modelling for the Zn-based microporous metal–organic framework(MOF) Zn4O(1,3,5-benzenetribenzoate)2, MOF-177, were performed over the 50–77 K and 0–40 bar ranges. The maximumexcess adsorption measured under these conditions varies over about 105–70 mg g−1. An analysis of the isotherms near saturation shows that hydrogen is ultimately adsorbedin an incompressible phase whose density is comparable to that of the bulk liquid. Theseliquid state properties observed under supercritical conditions reveal a remarkable effect ofnanoscale confinement. The entire set of adsorption isotherms can be well described using amicropore filling model. The latter is used, in particular, to determine the absolute amountsadsorbed and the adsorption enthalpy. When expressed in terms of absolute adsorption,the isotherms show considerable hydrogen storage capacities, reaching up to 125 mg g−1 at 50 Kand 25 bar. The adsorption enthalpies are calculated as a function of fractional filling and range from3 to 5 kJ mol−1 in magnitude, in accordance with physisorption. These results are discussedwith respect to a similar analysis performed on another Zn-based MOF,Zn4O(1,4-benzenedicarboxylate)3, IRMOF-1, presented recently. It is found that both materials adsorb hydrogen by similarmechanisms.