Molecular engineering toward large pore-sized covalent organic frameworks

In recent years, covalent organic frameworks (COFs) as designable crystalline porous polymers have attracted widespread attention because of their tunable structures and functionalities. In particular, the unique characteristics of COFs, such as readily controllable pore size, high surface area, editable pore surface environment, and exceptional chemical stability, provide a structural basis for loading large-sized organic, inorganic, and biological molecules for hetero-catalysis, energy storage, and other applications. In this review, we discuss state-of-the-art strategies for the structural design and synthesis, properties, and functionalities of large pore size two-dimensional and three-dimensional COFs, spotlighting recent breakthrough achievements and remarkable progress to guide further efforts in this field.