In methanol solution, 1,4,7-tri(pent-4′-yn-1′-yl)-1,4,7-triazacyclononane undergoes an intramolecular hydro-amination reaction to form an azoniaspiro[4.8]tridecane cation, 1-methylidene-8,11-di(pent-4′-yn-1′-yl)-8,11-diaza-5-azoniaspiro[4.8]tridecane. The azoniaspiro[4.8]tridecane cation, as its tetraphenylborate salt, has been characterized spectroscopically in solution and by X-ray studies in the solid state. Reactions of the azoniaspiro[4.8]tridecane that lead to other products are also discussed.