The nucleophilic substitution reactions of mono- and bis-spiro-2,2'-dioxybiphenyl cyclotriphosphazenes (3 and 4) with cyclopropanemethylamine (5) and aniline (6) were performed in the presence of trimethylamine in THF. Five novel cyclopropanemethylamino- and anilino-substituted spiro-2,2'-dioxybiphenyl cyclotriphosphazene derivatives (7-11) were obtained from these reactions. The molecular structures of the new cyclotriphosphazene derivatives (7-11) were characterized by elemental analysis, MALDI-TOF MS, FT-IR, and NMR (P-31 and H-1) spectroscopies. The structure of the spiro-(2,2'-dioxybiphenyl)-bis-(anilino)-cyclotriphosphazene (11) was also determined by single-crystal X-ray crystallography.