The germylone dimNHCGe (5, dimNHC = diimino N-heterocyclic carbene) was successfully prepared via the reduction of the germanium cation [dimNHCGeCl](+) with KC8. The molecular structure of 5 was unambiguously established by both NMR spectroscopy and single-crystal X-ray diffraction. The reactivity of 5 was investigated, revealing that it undergoes oxidative addition of HCl, CH3I, and PhI, accompanied by an unusual migration of the H, Me, and Ph groups from germanium to the carbene ligand. Related chemistry was also observed with C5F5N, which results in the migration of the fluorinated pyridine moiety to the carbene ligand. Compound 5 also undergoes cycloaddition with tetrachloro-o-benzoquinone to afford a Ge(IV) adduct.