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A series of structurally characterized magnesium and zinc complexes of the form L4-tBuPh–M{N(SiMe3)2}2[M = Mg (1) and Zn (2); L4-tBuPh= 1,3-diethyl-4,5-dimethylimidazolium-2-{N,N′-bis(4-tert-butylphenyl)amidinate}], L4-iPrPh–M{N(SiMe3)2}2[M = Mg (3) and Zn (4); L4-iPrPh= 1,3-diethyl-4,5-dimethylimidazolium-2-{N,N′-bis(4-isopropylphenyl)amidinate}], and L4-iPrPh–ZnEt2(5) bearing a zwitterionic-type neutral amidinate or N-heterocyclic carbene–carbodiimide (“NHC–CDI”) adduct and monoanionic amido or alkyl ligands have been reported. The synthesis of compounds 1–5was achieved by the direct addition of a “NHC–CDI” adduct to a corresponding metal bis(amide) or dialkyl reagent. All compounds 1–5exist as monomers in the solid state. In all cases, the metal (magnesium or zinc) centers adopt a distorted four-coordinate tetrahedral geometry bonded to one N,N′-chelated neutral zwitterionic ligand and two monoanionic amido or alkyl moieties. In contrast, sterically bulky zwitterionic amidinate 1,3-diethyl-4,5-dimethylimidazolium-2-{N,N′-bis(2,6-diisopropylphenyl)amidinate} (LDipp) upon treatment with lithium bis[(trimethylsilyl)amide], Li{N(SiMe3)2}, affords the NHC–lithium complex MeIEt–[Li{N(SiMe3)2}]2(6), in which one molecule of NHC (MeIEt = 1,3-diethyl-4,5-dimethylimidazol-2-ylidene) coordinates to one of the two lithium centers. In a similar way, the reaction between LDippand Mg{N(SiMe3)2}2allowed the formation of a NHC adduct of metal bis(amide), MeIEt–Mg{N(SiMe3)2}2(7), instead of a zwitterionic adduct of metal bis(amide). Alternatively, the synthesis of both compounds 6and 7was achieved by the direct addition of 1 equiv of NHC, i.e., MeIEt to Li{N(SiMe3)2} (2.0 equiv) and Mg{N(SiMe3)2}2(1.0 equiv) in benzene-d6, respectively. All compounds (1–7) were characterized by multinuclear {1H, 13C, and 29Si (for 1–4, 6, and 7) and 7Li (for compound 6)} magnetic resonance spectroscopy, mass spectrometry, elemental analysis, and single-crystal X-ray structural analysis. In addition, preliminary reactivity studies of zwitterion-supported metal complexes have been investigated. Furthermore, density functional theory calculations have been carried out to obtain the energetics of zwitterion-supported lithium and magnesium complexes.