The tris(2-mercapto-1-adamantylimidazolyl)hydroborato ligand, [Tm-Ad], has been synthesized via the reaction of 1-adamantyl-2-mercaptoimidazole with MBH4 (M = Li, K). [Tm-Ad]M has been used to synthesize a variety of compounds of the main-group and transition elements, including [TmA(d)]ZnI, {[Tm-Ad]GaI}[GaI4], {[Tm-Ad]GaCl} [GaCl4], {[Tm-Ad]GaGa[Tm-Ad]}[GaCl4](2), {[Tm-Ad](2)In} [InI4], [Tm-Ad]In-(kappa(2)-mim(Ad))Cl, [Tm-Ad]Ga -> B(C6F5)(3), [Tm-Ad]In -> B(C6F5)(3), and [Tm-Ad]Re(CO)(3). Structural characterization of [Tm-Ad]Re(CO)(3) demonstrates that the [Tm-Ad] ligand is more encapsulating than other [Tm-R] ligands, including [Tm-But], while IR spectroscopic studies indicate that the [Tm-Ad] and [Tm-But] ligands have very similar electron-donating properties.