Rylene diimides (RDIs) derivatives are an important class of functional organic dyes. With unique electron-defi- cient conjugated backbones and excellent photoelectronic properties, these polycyclic aromatic hydrocarbons have wide applications in organic field effect transistors, organic photovoltaic devices, and biomedical sensing. Precise modification of the RDIs skeletons can not only regulate molecular energy levels, but also facilitate controllable assembly between π-molecules, which is an effective means to create new π-molecular materials. In the early stage, due to the limitation of synthetic methods, only modifications on the bay positions of RDIs can be achieved. However, the introduction of substituents on these sites would distort the π-plane of RDIs and was not conducive to effective π-stacking between molecules. The selective modifications of RDIs skeletons on the ortho positions do not affect the planarity of the skeletons, which have received much attention in recent years, leading to a series of efficient strategies toward ortho-functionalized RDIs. The methods of ortho-C—H bond functionalization of RDIs such as perylene diimides and naphthalene diimides, and the influence of ortho- modification on the photoelectronic properties and assembly of RDIs derivatives are summarized.

Key words: rylene diimides, π-conjugated materials, C—H bond activation, transition metal catalysis