The synthesis of phosphazene cyclic trimers with azido side groups and aryloxy, alkoxy, or dialkylamino cosubstituent groups was accomplished. The compounds have the basic structure N3P3(R)(x)(N-3)(6-x), where R represents phenoxy, trifluoroethoxy, dimethylamino, or diethylamino groups and x = 3-5. Experiments were also conducted to determine the ability of these materials to undergo a reaction unique to azido compounds known as nitrene insertion. The aryloxy derivative, N3P3(OC6H5)(5)(N-3), yielded a nitrene insertion product when heated with 1-phenylnonane at 280 degrees C. The alkoxy derivative, N3P3(OCH2CF3)(5)(N-3), produced a nitrene insertion product when ultraviolet irradiated in an aliphatic solvent. The dialkylamino derivative, N3P3(N(CH3)(2))(4)(N-3)(2), did not undergo nitrene insertion. The aryloxy and alkoxy azido trimers reacted with various phosphorus(III) compounds to form phosphinimines via the Staudinger reaction. Finally, sodium phenoxide displaced azides from both the alkoxy- and aryloxyphosphazene trimers while n-butylamine displaced only the azide on the alkoxy trimer.