Porous Organic Cages for CO₂ Capture and Confined Reduction

Porous organic cages (POCs) are discrete molecular materials that combine intrinsic porosity with solution processability and well-defined, chemically tunable cavities. These features make them attractive for CO₂ capture and selective gas separation, and more recently for chemical transformations under confinement. Across amorphous and crystalline solids, as well as membrane and composite systems, POC-based materials enable selective CO₂ uptake. However, their performance is governed by how molecular structure translates into accessible pore environments through solid-state organization. In catalysis, POCs can promote local CO₂ enrichment and facilitate interaction with active sites, but their role extends beyond simple concentration effects. Even when not directly involved in the reaction, the POC's cavity can influence catalytic performance through confinement effects or host-guest interactions, as illustrated by hybrid systems and porphyrinic cages incorporating guest species. This Minireview examines recent advances in the use of POCs to integrate CO₂ capture with confined reduction. We discuss how cage structure, cavity size, internal functionality, solid-state packing, and processing strategies govern gas binding, transport, and accessibility, and how confinement influences catalytic behavior. These studies highlight emerging design principles but also current limitations, and point to clearer structure-function relationships to enable applications under realistic conditions.