Abstract Cooperative cluster metalation and ligand migration were performed on a Zr‐MOF, leading to the isolation of unique bimetallic MOFs based on decanuclear Zr 6 M 4 (M=Ni, Co) clusters. The M 2+ reacts with the μ 3 ‐OH and terminal H 2 O ligands on an 8‐connected [Zr 6 O 4 (OH) 8 (H 2 O) 4 ] cluster to form a bimetallic [Zr 6 M 4 O 8 (OH) 8 (H 2 O) 8 ] cluster. Along with the metalation of Zr 6 cluster, ligand migration is observed in which a Zr–carboxylate bond dissociates to form a M–carboxylate bond. Single‐crystal to single‐crystal transformation is realized so that snapshots for cooperative cluster metalation and ligand migration processes are captured by successive single‐crystal X‐ray structures. In 3+ was metalated into the same Zr‐MOF which showed excellent catalytic activity in the acetaldehyde cyclotrimerization reaction. This work not only provides a powerful tool to functionalize Zr‐MOFs with other metals, but also structurally elucidates the formation mechanism of the resulting heterometallic MOFs.