Covalent organic frameworks (COFs) are a class of crystalline porous polymers that allow the atomically precise integration of organic units to create predesigned skeletons and nano-pores. Since the seminal work of Yaghi on covalent organic frameworks

this subject has attracted extensive interest not only from chemists’ science and organic synthesis

but also from various researchers in the fields of gas storage

heterogeneous catalysis

semi-conduction and photoconduction. This review describes the building blocks of COFs and synthetic methods. The applications are also studied and evaluated. Concerning COFs for future research

some suggestions are proposed and conclusions are given.