N-Lithio-N-trimethylsilyl-9-amino-9-borabicyclo[3.3.1]nonane (2) was prepared from the reaction of N-trimethylsilyl-9-amino-9-borabicyclo-[3.3.1]nonane (1) with rert-butyl lithium; 2 crystallizes as a trim er with a planar N3Li3 ring. The nitrogen atoms are tetrahedrally coordinated, but should be treated as sp2 hybridised, because the BN double bond, typical of aminoboranes, is retained.