Aminodiphenylphosphines are deprotonated by alkyllithium reagents to give the corresponding iminophosphide/ phosphinoamide ions: lithium(neopentyl) (diphenylphosphino)amide (3), lithium (isopropyl) (diphenylphosphino)amide (4), and lithium (2,4,6-tri-tert-butylphenyl)(diphenylphosphino)amide (5). Derivative 3 crystallizes in the monoclinic space group P2(1)/c with Z = 4, a = 17.717(2) Angstrom, b = 11.167(2) Angstrom, c = 22.151(1) Angstrom, beta = 104.35(1)degrees, R1 = 0.064, and wR2 = 0.184 at -73 degrees C. Derivative 4 crystallizes in the orthorhombic space group Pna2(1) with Z = 4, a = 20.557(4) Angstrom, b = 10.475(2) Angstrom, c = 17.982(4) Angstrom, R1 = 0.044, and wR2 = 0.089 at -70 degrees C. Derivative 5 crystallizes in the monoclinic space group C2/c with Z = 8, a = 47.256(6) Angstrom, b = 9.126(2) Angstrom, c 18.246(2) Angstrom, beta = 104.67(1)degrees, R1 = 0.064, and wR2 = 0.165 at -73 degrees C. The solid-state structures of compounds 3 and 4 consist of approximately centrosymmetric dimers containing a Li2N2 rhombus with each lithium ion bound by both anions through their nitrogen atoms and by an ether solvate to give approximate trigonal planar coordination geometry. In some cases, weak second-sphere dipole interactions are suggested by relatively short P ... Li distances. The anions of 3 and 4 adopt cis conformations. In contrast, 5 is a monomer in the solid state. The anion of 5 adopts a trans conformation and the cation, which is bound by two ether solvates, exhibits approximately trigonal planar geometry.