This review summarizes the recent research progress in the metalation of metal–organic frameworks, spanning the design principles, synthetic strategies, and potential applications.

An unprecedented polynuclear cobalt complex with a [Co₂₄] macrocycle in the presence of [Co(H₂O)₆]²⁺ has been prepared and characterized. In this complex, [Co(H₂O)₆]²⁺ not only acts as a counterion to balance the negative charge of the 2D layer, but may also serve as a template in the assembly of the [Co₂₄] macrocyclic complex through hydrogen-bond interactions. Magnetic analyses indicate that the title compound shows homometallic ferrimagnetic behavior.