The twofold addition of Ga-H to C C triple bonds (hydrogallation) did not succeed by treatment of alkynes with an excess of dialkylgallium hydrides. In contrast, double hydrogallation was easily achieved by the reactions of H-GaCl2 with trimethylsilyl-substituted alkynes [trimethylsilylphenylethyne and 1,4-bis(trimethylsilylethynyl) benzene) in appropriate stoichiometric ratios. The monoalkyne yielded the compound [H5C6-CH2-C(SiMe3)(GaCl2)(2)](2), 1, which was only sparingly soluble in n-hexane. Crystal structure determination revealed a dimeric formula unit possessing two parallel Ga2Cl2 heterocycles in the solid state. Treatment of the dialkyne with four equivalents of the hydride gave a colorless precipitate, which was completely insoluble in, hydrocarbons. Addition of diethyl ether to both products afforded soluble and monomeric etherates 1 (OEt2)(2) and 2 in which the two or four gallium atoms, respectively, were coordinated by ether molecules. Preliminary experiments with simple Lewis bases showed the principle capability of 1 to act as an effective chelating Lewis acid. Adducts of the type [HSC6-CH2-C(SiMe3)(,GaCl2)(GaCIX)(mu-Cl)](-)(4-6) resulted upon treatment With halide ions (X = Cl, Br, l).