Porphyrins are macromolecular heterocyclic compounds substituted by various functional groups at the meso- or β-position. Free base porphyrins can coordinate with many metal ions in the porphyrin center to form metal complexes, also known as
metalloporphyrins. Owing to its larger π-aromatic system, porphyrins exhibit excellent chemical and thermal stability and unique photophysical and electrochemical properties, which can be tuned by substitution patterns on porphyrins and coordinating metal ions. In addition to the coordination of metal ions at the center of porphyrins, the periphery of porphyrins can also bind to metal ions. The complex binding mode enables porphyrins to form ideal molecular cages or framework solids. More importantly, porphyrins are critical in many biological processes, and they have powerful biological properties such as biocompatibility, convenient and efficient clearance, long residence time in tumors, few side effects, and mimicking various biological properties function, which is very useful for biomedical applications. As an emerging material, MOFs have the advantages of ultra-high porosity, tunable pores, tunable structure and composition, unsaturated metal sites, and functional diversity. And nanoscale MOFs (NMOFs) are very suitable as delivery systems. Loading porphyrins into MOF channels and modifying porphyrins on the surface of MOFs is an effective strategy to synthesize porphyrin-MOFs, which can enhance the stability of porphyrins and facilitate potential applications. In addition, free-base porphyrins and metalloporphyrins can also be used as organic linkers to assemble porphyrin and metalloporphyrin MOFs, respectively. This can prevent the self-aggregation and self-quenching of porphyrin and improve its physicochemical properties.