The reaction of a bifunctional hydroxy N-heterocyclic carbene (NHC-OH)ligand with alkyl-aluminum(III) derivatives appears to be dependent of the precursor used.The expectedalkoxy-NHC metallated productis indeed obtained with Al(iBu)3. In contrast, the sterically hindered[Al(iBu)(OAr)2] (OAr = 2,6-di-tertbutyl-4-methylphenoxy) displays reactivity at the carbeneand affords an imidazolium-aluminate zwitterion. The non-innocence of the Al-NHC motif is further highlighted by the heterolytic cleavageof the phenol O-H bond across the Al-CNHCbondfrom Al(O-NHC)X2derivatives (X = iBu, OAr).