The twelve membered and eighteen membered cyclosiloxazanes [Me2SiOSiMe2N(H)SiMe2O]2(3) and [Me2SiOSiMe2N(H)SiMe2O]3(4) have been obtained as colourless liquids from the reaction of 1,5-Dichlorohexamethyltrisiloxane with ammonia at-50 °C without any solvent. For compound3and4, the yield is 30 % and 43 %, respectively. The treatment of3with two equivalents ofn-butyllithium in n-hexane leads in almost quantitative yield (93 %) to the dilithiumsilylamide [Me2SiOSiMe2N(Li)SiMe2O]2(5). Compound5can be isolated at room temperature and recrystallized from benzene without any decomposition or contraction of the ring size. An X-ray structure determination on [Me2SiOSiMe2N(Li)SiMe2O]2(5) reveals a waved crown-like twelve membered Si6N2O4-cycle. Each of the two lithium ions is coordinated by two nitrogen and two oxygen atoms leading to a square pyramid, in which the metal occupies the apex. The two square-pyramidal coordination figures are located above and below the waved crown-like Si6N2O4-ring sharing a common edge by the atoms N(1) and N(2). All synthesised compounds have been characterised by spectroscopic methods. Because of the lower solubility of the dilithiumsilylamide5, only a1H-NMR could be applied for further characterisation in solution.