The aim of this thesis is to explore the power and the limits of classical and quantum molecular modelling, for the investigation of the adsorption properties of microporous crystalline materials. The materials analyzed are metal organic frameworks (MOFs) and covalent organic frameworks (COFs), two classes of frameworks that in the last two decades attracted the interest of the scientific community due to their limitless possibility of tunability and their remarkable properties. The four articles that are gathered in this document describe the advances in (1) modelling the interaction of polar molecules with MOFs' open metal sites, (2) computing the micorpore volume that can be occupied by gas molecules, (3) benchmarking the different protocols that are used to estimate partial charges in the frameworks and (4) constructing a full workflow to evaluate the performance of COFs for carbon capture and storage, from just their crystal structure.