MOFs, also known as porous coordination polymers, are hybrid porous materials with one-, two-, or three-dimensional structures formed by the self-assembly of organic ligands and metal ions/clusters through coordination bonds. Since the late 1990s, when MOFs with stable and robust frameworks were discovered, pioneering work in the development of MOFs has made them a well-suited and popular approach in many different fields, such as energy and medicine. Compared with other nanoporous materials, MOFs are typically characterised by high porosity, large specific surface area, tuneable structure, and ease of functionalization. The properties of MOFs arise from the combination of the component building units: metal centres and organic linkers. Metal ions or clusters form the central building blocks of MOF structures, imparting rigidity and stability to the coordination network with specific structures and properties. Organic linkers, the other essential building units that serve as bridges, can be adjusted to modulate functionalities such as pore size, chemical reactivity and adsorption selectivity of materials. By purposeful selection of metal centres and organic linkers, MOFs with controllable pore structure, higher stability and modifiable active sites can be designed to meet specific application requirements.