A bifunctional imidazolium functionalized Zr-based metal–organic framework, (I⁻)Meim-UiO-66, was successfully prepared, which can serve as an efficient heterogeneous catalyst towards the capture and coupling of CO₂ with epoxides.

A mesoporous cationic Cr-based metal–organic framework (MOF), FJI-C10, has been obtained and exhibited excellent performances in chemical fixation of CO₂ into cyclic carbonates under co-catalyst free and mild conditions.

We present a facile approach to encapsulate functional porous organic cages (POCs) into a robust MOF by an incipient‐wetness impregnation method. Porous cucurbit[6]uril (CB6) cages with high CO₂ affinity were successfully encapsulated into the nanospace of Cr‐based MIL‐101 while retaining the crystal framework, morphology, and high stability of MIL‐101. The encapsulated CB6 amount is controllable. Importantly, as the CB6 molecule with intrinsic micropores is smaller than the inner mesopores of MIL‐101, more affinity sites for CO₂ are created in the resulting CB6@MIL‐101 composites, leading to enhanced CO₂ uptake capacity and CO₂/N₂, CO₂/CH₄ separation performance at low pressures. This POC@MOF encapsulation strategy provides a facile route to introduce functional POCs into stable MOFs for various potential applications.

This review provides a comprehensive introduction to the definition and development of host@MOF materials, where organic macrocycles, cages, metal–organic polyhedrons or enzymes have been encapsulated in the pores of metal–organic frameworks (MOFs).