Reactions of 2-XB(5)H(8) (X = Br or Cl) with secondary or tertiary silylamines proceed with elimination of hydrogen halides and/or halosilanes and attachment of amino groups to the clusters. Reaction of 2-BrB5H8 with (Me(3)Si)2(N)H produces 2-[(Me(3)Si)(2)N]B5H8 in 57% yield. Other bis(silyl)amines react analogously. With (t-Bu)(Me(3)Si)NH, 2-BrB5H8 produces 2- [(Me(3)Si)(t-Bu)N]B5H8 and hypho-2,3-mu-(t-BuNH)B5H10. (t-Bu)(Et(3)Si)NH reacts analogously. Low temperature analysis of the (t-Bu)(Me(3)Si)NH reaction in dichloromethane solution via B-11 NMR spectroscopy discloses a dual reaction pathway producing a 2-aminopentaborane and a proposed arachno-2,3-mu-(t-BuNH)B5H8 intermediate which subsequently reacts with boranes to form hypho-2,3-mu-(t-BuNH)B5H10. When the above reaction is carried out in B5D9 solution, normal nido-[(t-Bu)(Me(3)Si)N]B5H8 and partially deuterated hypho-2,3-mu-(t-BuNH)B5H10 is formed. Reaction of 2-[(Me(3)Si)(2)N]B5H8 with BCL produces 2-[(Me(3)Si)(2)N . BCl3]-B5H8, and with (t-Bu)CN produces 2,3-mu-(t-BuCH=N)-2-[(Me(3)Si)(2)N]B5H7.