A large series of new N-phosphorylphosphoranimines that bear potentially reactive functional groups on both phosphorus centers were prepared by silicon-nitrogen bond cleavage reactions of N-silylphosphoranimines. Thus, treatment of the N-silylphosphoranimines, Me3SiN=P(Me)(R)X (R)X (R = Me, Ph; X = OCH2CF3 and R = Me, X = OPh), with phosphoryl chlorides, RP(=O)Cl-2 (R' = Cl, Me, Ph), readily afforded the corresponding N-phosphoryl derivatives, R'P(=O)(Cl)-N=P(Me)(R)X, in high yields. Subsequent reaction with 1 or 2 equiv of the silylamine, Me3SiNMe2, resulted in ligand exchange at the phosphoryl (P=O) group to give the P-dimethylamino analogues, R'P(=O)(NMe2)N=P(Me)(R)X (R' = Cl, NMe2, Me, Ph; R = Me, Ph; X = OCH2CF3, OPh). These new N-phosphorylphosphoranimines (and one thiophosphoryl analogue) were obtained as thermally stable, distillable liquids and were characterized by NMR (H-1, C-13, and P-31) spectroscopy and elemental analysis. One member of the series, Cl2P(=O)N=P(Me)(Ph)OCH2CF3 (4), was also studied by single-crystal X-ray diffraction which revealed that the formal P(O)-N single bond [1.55(1) Angstrom] is shorter than the formal N=PR2X double bond [1.60(1) Angstrom]. Such structural features are compared to those of similar compounds and discussed in relationship to the unexpected thermolysis pathways observed for these N-phosphorylphosphoranimines, none of which produced poly(phosphazenes).