Reactivity differences between silicon and germanium as supporting ligands in PEP-pincer type palladium complexes (E = Si, Ge) were clarified by experimental and theoretical studies. An η 2 -(Ge-H)palladium(0) complex, which was synthesized and structurally characterized for the first time, exhibited higher reactivity for hydrometallation of ethylene than the silylanalogue. The resulting PGeP-ethylpalladium(II) complex was more stable than the silyl-analogue, which allowed its isolation and structural analysis by X-ray crystallography. Formation of a [a]