Catalytic acylation of nitriles with esters in the presence of 10 mol% NdNa 8 (O t Bu) 10 (OH) is developed. The procedure is suitable for both enolizable and nonenolizable esters and affords β-ketonitriles in moderate to high yields. The heterometallic alkoxide cluster NdNa 8 (O t Bu) 10 (OH) is structurally characterized by X-ray diffraction, and a mechanism for the production of β-ketonitriles using the cluster is proposed and verified. Recently we found that the clusters [Ln 2 Na 8 (OCH 2 CH 2 -NMe 2 ) 12 (OH) 2 ](Ln=Nd, Pr, Sm, Y, Ho) are active singlecomponent catalysts for the polymerization of ε-caprolactone as well as trimethylene carbonate. The reactivity of these clusters is much higher than those of the related lanthanide alkoxide and sodium alkoxide compounds, indicating that a cooperative effect may exist between the two different metals in these ring-opening polymerization reactions [13]. These results encouraged us to study further the application of heterometallic alkoxide clusters containing lanthanide and sodium in organic synthesis. Here, we report the synthesis of heterometallic tert-butoxide clusters containing lanthanide and sodium LnNa 8 (O t Bu) 10 (OH) (Ln=Nd, Sm, Yb) and their catalytic activity for the acylation of nitriles with esters.