Metal-organic frameworks (MOFs) with extended cage structures have received considerable attention because of their topologically extraordinary architecture and potential applications. Thus far, a myriad of molecular-cage metal organic frameworks (MC-MOFs) have been reported, including HKUST, ZIFs, PCN, and UIO. These structures are characteristic of their large pockets and confined entrance apertures. The uniquely interconnected yet compartmentalized void space inside cage-like metal-organic frameworks renders them suit for a wide range of applications in catalysis, gas storage, and gas separation. Compared with N- coordinative groups such as azole or pyridine, O-coordinative groups based on carboxylate have more coordination modes and stronger bonding ability, providing more structural possibilities in designing cage-like metal frameworks. Firstly, a carboxylate group can coordinate with multiple metal ions simultaneously, and its coordination modes are not limited to the monodentate and chelation coordination, but also include the bridging coordination. Secondly, when combined with different metal ions, carboxylate groups can form diverse metal clusters. Compared to the single metal nodes, the presence of polyhedral clusters not only increases the possibility of assembling the framework into a cage, but also enriches the topological types of the framework. In addition, carboxylate groups are prone to deprotonation with a negative charge when they coordinate. They can form neutral frameworks with positively charged metal centers, thereby reducing the dependence of the framework on guest molecules and improving the stability of the material. In this chapter, the focus will be on some typical compounds to discuss the relevant cage structures according to the number of carboxylate groups in the ligand.