Nanoporous materials are a key family of systems in the domain of materials science, with high scientific and technological importance. Nanoporous frameworks are a large and diverse family of supramolecular materials, whose chemical building units (organic, inorganic, or both) are assembled into a three-dimensional architecture with well-defined connectivity and topology, featuring intrinsic porosity. Because of the presence of pores of controllable dimensions in their structure, they present a solid/fluid interface with high surface area and tunable chemistry. Many industrial processes are based on adsorption in these nanoporous frameworks and are particular key to addressing contemporary challenges in the areas such as energy production, conversion and storage, fluid separation, environmental sciences, medicine, etc. In some cases, the adsorbed molecules form chemical bonds with the host material, and some applications rely on this chemisorption, such as gas sensing, chemical hydrogen storage, and probably most commonly, heterogeneous catalysis. On the other hand, many industrial applications are based on the phenomenon of physisorption, where no chemical bonds are formed and relatively weak interactions are involved (van der Waals attraction, Coulombic interactions, etc). Such is the case of applications like gas storage, gas purification, fluid separation, drug release, etc. Molecular simulation of physisorption is a research field with a long history, and a variety of computational methods have been developed to study both the thermodynamics and dynamics of the confined phase. 11 However, because physisorption does not create chemical bonds between the host material and guest molecules, most of these methods rely on a "rigid host" approximation. In this approach, the nanoporous material is considered as rigid and the presence of the adsorbed molecules does not change its structure or its electronic state: the adsorbent acts as an "external confinement field" on the adsorbed phase. However, this approach finds important limitations with the ever-increasing number of nanoporous frameworks exhibiting large-scale flexibility (also called "soft porous crystals" ), whether due to thermal motions, or through strain induced by external stimulation.