[CP*Ir(C2H4)(N2Ar)][BF4] (1; Ar = p-C(6)H(4)OMe) reacts with PMe(3) to give [Cp*Ir(PMe(3))(2)(N2Ar)][BF4] (4), which has been shown by an X-ray structure determination and by N-15 NMR spectroscopy to possess the aryldiazenido ligand bound with doubly-bent geometry. As is the case in 1, the complexes [Cp*Ir(PPh(3))(N2Ar)][BF4] (2) and [Cp*Ir{P(p-tol)(3)}(N2Ar)][BF4] (3) have the N2Ar ligand bound with singly-bent geometry. This has been demonstrated by an X-ray structure determination for 3. Complexes 2 and 3 react with PMe(3) to give [Cp*Ir(PPh(3))(PMe(3))(N2Ar)][BF4] (5) and [Cp*Ir{P(p-tol)(3)}(PMe(3))(N2Ar)][BF4] (6), and 2 reacts with CO or CN- to give [Cp*Ir(CO)(PPh(3))(N2Ar)][BF4] (7) or Cp*Ir(CN)(PPh(3))(N2Ar) (8). All these reactions are shown by N-15 NMR to involve the transformation of the N2Ar ligand from singly-bent to doubly-bent as a consequence of coordination by the incoming ligand. Diphos (Ph(2)P(CH2)(2)PPh(2)) reacts with 1 to give [Cp*Ir(diphos)(N2Ar)][BF4] (9), but no complex of stoichiometry [Cp*Ir(PPh(3))(2)(N2Ar)][BF4] could be obtained from 1 or 2 with excess PPh(3); this complex is presumably sterically disfavored. Crystal structures : 3, T = 295 K, orthorhombic, space group P2(1)2(1)2(1), 2 = 4; a = 12.974(2) Angstrom; b = 13.449(2) Angstrom, c = 16.213(4) Angstrom, V = 2829.0 Angstrom(3), R(F) = 0.032 for 2974 data (I-0 greater than or equal to 2.5 sigma (I-0)) and 241 variables; 4, T = 295 K, monoclinic, space group P2(1)/n, Z = 4; a = 9.906(2) Angstrom, b = 12.084(3) Angstrom, c = 30.545(6) Angstrom, beta = 93.296(13)degrees, V = 3650.2 Angstrom(3), R(F) = 0.029 for 3606 data (I-0 greater than or equal to 2.5 sigma (I-0)) and 422 variables.