Construction of Shape‐Persistent Porous Organic Cages

Porous organic cages (POCs) are an emerging class of crystalline porous material composed of discrete covalent organic cage molecules assembled through noncovalent interactions. Shape persistence, defined as the ability to retain a well‐defined three‐dimensional cavity after guest removal, is critical for POCs to exhibit permanent porosity and reliable functional performance. However, many POCs suffer from structural collapse or performance degradation upon complete guest removal. Constructing shape‐persistent POCs therefore provides an effective strategy to address this challenge. This review summarizes synthetic strategies for constructing shape‐persistent POCs through bonding chemistry, including imine bonds, aromatic ether bonds, and other robust linkages, as well as through postsynthetic modifications (PSM). We discuss how bonding chemistry governs conformational rigidity and illustrate the influence of shape persistence on material performance through representative examples. Overall, bonding chemistry provides the structural foundation for PSM, while these two approaches complement each other in enabling POCs with desired structures, permanent porosity, and targeted applications.