Metal-organic frameworks (MOFs) are excellent supports for metal nanoparticles (NPs), but the interactions between metal NPs and inorganic nodes of MOFs are weak because of the presence of organic ligands. Here, we present a strategy for strengthening the metal-NP/MOF interactions through controlled deligandation of the metal/MOF composites by thermal transformation. The controlled deligandation of MOF results in the formation of a “quasi-MOF,” which has a transition-state structure between the porous MOF and metal oxide. The obtained metal/quasi-MOF composites not only retain a porous structure but also achieve a strong interaction between the metal NPs (i.e., Au) and the inorganic nodes (i.e., Cr–O) of the quasi-MOF, leading to dramatically enhanced catalytic performance in the low-temperature oxidation of carbon monoxide (CO). The present findings could open new avenues for the design of superior heterogeneous catalysts.