The reactions of the arachno-4,6-C2B7H13 carborane with the secondary and primary amines, Me2NHBH3 and (BuNH2BH3)-Bu-t, in ionic liquid media result in both boron-insertion into the cage at a position across the two cage-carbons and additional hydrogen-elimination via the reaction of a hydridic B-H with a protonic amine N-H hydrogen to produce the 6-(RR'N)-nido-5,7-C2B8H11 carboranes. Computational characterizations of these compounds and the previously reported 6-ClC6H4-9-(RR'N)-nido-6-NB9H10 azaboranes indicate that the amine-nitrogens form unique exopolyhedral dative B=N double bonds with a cage-boron.