Adduct complexes Ga6(μ-CH2)9(DMAP)3(THF) and Ga8(μ-CH2)12(PEt3)x (x = 4 and 6) could be obtained upon crystallization of Ga8(CH2)12 from THF/DMAP (hard Lewis bases) and PEt3 (soft Lewis base), respectively. Mixed methyl/methylene {Ga4} species with either bridging aryloxy, thiophenolato, or arylamido ligands were accessible via the treatment of Ga8(CH2)12 with phenols (HOC6H2Me3-2,4,6 and HOC6H3Me2-2,6), thiophenol HSC6H2Me3-2,4,6, and anilines (H2NC6H2Me3-2,4,6 and H2NC6H3Me2-2,6). Such tetrametallic complexes Ga4(μ2-CH2)2(CH3)4(μ2-XAr)4 (X = O, S, NH) are isostructural, displaying an adamantane-like core structure. The sterically more demanding phenol HOC6H3tBu2-2,6 afforded the {Ga5} cluster Ga5(μ2-CH2)6(OC6H3tBu2-2,6)3(THF)2 with the gallium centers exclusively bridged by methylene groups. Treatment of Ga8(CH2)12 with other protic substrates HOR/H2NR′, including HOCH2tBu, HOSi(OtBu)3, H2NC6H3iPr2-2,6, and H2NSiPh3 point to a pronounced stereoelectronic dependency and intricacy of such transformations but provided helpful information about potential side products such as [(CH3)2Ga(μ-X)]2 (X = OR, HNR′) and reaction intermediates. Efficient methylene → imido transformations using Ga8(CH2)12/aniline mixtures could not be implemented.