The formation and bond activation reactions of the d0 carbene complexes MCHCN+ (M = Sc, Y) are presented. Sc+ and Y+ dehydrogenate acetonitrile to produce the metallocarbenes. The carbene complexes are less reactive towards hydrocarbons than their bare metal ion counterparts, but will activate CH, OH, and NH bonds through a four-centered intermediate. Labeling studies indicate that reactions with olefins proceed by migratory insertion after initial CH activation, and that subsequent ligand coupling produces metal-bound nitrite products. Oletin metathesis reactions are not observed due to the electron-withdrawing characteristics of the CN substituent and the electrophilicity of the metal centers.