The hybrid inorganic-organic heterocycles, pentachlorocyclocarba phosphazene, (ClCN)₂(Cl₂PN) and triachlorocyclocarbathiazene, (ClCN)₂(ClSN) were synthesized and their reaction chemistry explored with emphasis on dealkylation reactions of the heterocycles with tertiary amines. Reactions of (ClCN)₂(Cl₂PN) were carried out with bicyclic, unsymmetric and sterically hindered tertiary amines as well as aminomethyl ferrocenes. In all cases, the C-Cl bonds of the carbaphosphazene were found to react with the tertiary amines resulting in the cleavage of an alkyl group and regiospecific substitution of the dialkylamino group on the ring carbon atoms of the heterocycle. While bicyclic amines were found to undergo ring opening, the preference of the cleaved group in the case of unsymmetrical amines were found to depend on the stability of the carbocations formed. Similar dealkylation was observed in the reactions of the carbathiazene (ClCN)₂(ClCN) with tertiary amines.