Unlike in conventional organic solvents where transition metal catalysts are required, decaborane olefin-hydroboration reactions have been found to proceed in biphasic ionic-liquid/toluene mixtures with a wide variety of olefins, including alkyl, alkenyl, halo, phenyl, ether, ester, pinacolborane, ketone, and alcohol-substituted olefins, and these reactions now provide simple high-yield routes to 6-R-B10H13 derivatives, Best results were observed for reactions with bmimX (1-butyl-3-methylimidazolium, X = Cl- or BF4-) and bmpyX (1-butyl-4-methylpyridinium, X = Cl- or BF4-). Both the experimental data for these reactions and separate studies of the reactions of B10H13- salts with olefins indicate a reaction sequence involving (1) the ionic-liquid-promoted formation of the B10H13- anion as the essential initial step, (2) the addition of the B10H13- anion to the olefin to form a 6-R-B10H12- anion, and finally, (3) protonation of 6-R-B10H12- to form the final neutral 6-R-B10H13 product. The 6-R-B10H13 derivatives also undergo ionic-liquid-mediated dehydrogenative alkyne-insertion reactions in biphasic bmimCl/toluene mixtures, and these reactions provide high yield routes to 3-R-1,2-R'(2)-1,2-C2B10H9 ortho-carborane derivatives,