“…Covalent organic frameworks (COFs) make up an emerging class of two-dimensional (2D) and three-dimensional (3D) crystalline porous polymers, with an exceptional diversity of types and shapes, due to the high accessibility and diversity of organic building blocks. − Meanwhile, these materials usually exhibit low densities, large specific surface areas, high thermal stabilities, and controllable structures, rendering them good candidates for various potential applications, including gas adsorption, − organic catalysis, − photocatalysis, − electrochemistry, − molecular recognition, fluorescence sensing, − etc. COFs are constructed typically by interconnecting the molecular building blocks; therefore, the reversibility of the condensation reactions for the synthesis of highly crystalline COFs is particularly critical, while the formation of strong covalent bonds often leads to poor crystallinity or even an amorphous network.…”