An approach to the latter is to use organic linkers that undergo colour changes upon an electronically stimulated redox process. In this regard MOFs that contain ligands based on rylene diimides are particularly attractive due to the rich chemistry of such systems and their application in electronic and photoactive materials. In the context of MOFs, by far the most studied rylene diimides are naphthalene diimides (NDIs). 17 NDI-containing MOFs have been extensively developed and include seminal examples of electrochromic materials. Despite the interesting properties that can be developed using NDI components, such systems are limited by the inherent properties of the NDI manifold. An alternative is to explore rylene diimide analogues such as perylene diimides (PDIs). PDIs exhibit the similarly robust behaviour as NDIs but combine distinct HOMO-LUMO energy gaps, leading to different electro-and photo-chemical properties and colours, along with greater potential for core functionalisation leading to potential adaptability. Interestingly, PDIs have received far less attention in terms of their incorporation into MOFs.