Siladiazoles C6H4(NH)2SiPh2 (7) and C6H4(NH)2SiPhMe (8) and cyclic siloxazanes C6H4(NHSiPh2)2O (9) and C6H4(NHSiPhMe)2O (10A/10B) are obtained from reactions of 1,2-(NH2)2C6H4 with Ph2SiCl2, PhMeSiCl2, (Ph2SiCl)20, and (PhMeSiCl)2O, respectively. The 8/PhMeSiCl2/Et3N reaction produces skeletally stabilized chlorodisilazane diastereomers C6H4(NH)SiPhMe(N)Si(Cl)PhMe (11A/11B); the latter are quantitatively aminated by i-PrNH2 to C6H4(NH)SiPhMe(N)Si(i-PrNH)PhMe diastereomers 13A/13B. 10A/10B, 11A/11B, and 13A/13B are all formed as 1:1 diastereomer mixtures; there is no evidence for diastereoselectivity in their formation. PhMeSiCl2/PhMeSi(i-PrNH)2 (14)/Et3N reactions yield the redistribution product PhMeSi(i-PrNH)Cl (15) and no acyclic or cyclic disilazanes. 7-11 and 13-15 were characterized by spectral data (MS, IR, and H-1 and Si-29 NMR). 9 was further characterized by X-ray crystallography : orthorhombic, Fdd2, a = 18.211 (6) angstrom, b = 28.344 (11) angstrom, c = 9.752 (3) angstrom, V = 5033 (3) angstrom3, Z = 8, R = 0.0325, R(w) = 0.0416. The absence of diastereoselective silazane and siloxazane formation and the contrast that exists with the formation of structurally analogous phosph(III)azanes are discussed.