Harnessing Multi‐Center‐2‐Electron Bonds for Carbene Metal–Hydride Nanocluster Catalysis

N‐Heterocyclic carbene (NHC) ligands possess the ability to stabilize metal‐based nanomaterials for a broad range of applications. With respect to metal–hydride nanomaterials, however, carbenes are rare, which is surprising if one considers the importance of metal–hydride bonds across the chemical sciences. In this study, we introduce a bottom‐up approach leveraging preexisting metal–metal m‐center‐n‐electron (mc‐ne) bonds to access a highly stable cyclic(alkyl)amino carbene (CAAC) copper–hydride nanocluster, [(CAAC)6Cu14H12][OTf]2 with superior stability compared to Stryker’s reagent, a popular commercial phosphine‐based copper hydride catalyst. Density functional theory (DFT) calculations reveal that the enhanced stability stems from hydride‐to‐ligand backbonding with the π‐accepting carbene. This new cluster emerges as a highly efficient and selective copper–hydride pre‐catalyst across six reaction classes, thereby providing a bench‐stable alternative for catalytic applications.