The complex [{Ir(mu-Pz)(CNBut)(2)}(2)] (1) undergoes double protonation reactions with HCl and with HO2CCF3 to give the neutral dihydride complexes [{Ir(mu-Pz)(H)(X)(CNBut)(2)}(2)] (X = Cl, eta(1)-O2CCF3), in which the hydride ligands were located trans to the X groups and in the boat of the complexes, both in the solid state and in solution. The complex [{Ir(mu-Pz)(H)(Cl)(CNBut)(2)}(2)] evolves in solution to the cationic complex [{Ir(mu-Pz)(H)(CNBut)(2)}(2)(mu-Cl)]Cl. Removal of the anionic chloride by reaction with methyltriflate allows the isolation of the triflate salt [{Ir(mu-Pz)(H)(CNBut)(2)}(2)(mu-Cl)]OTf. This complex undergoes a metathesis reaction of hydride by chloride in CDCl3 under exposure to the direct sunlight to give the complex [{Ir(mu-Pz)(Cl)(CNBut)(2)}(2)(mu-Cl)]OTf. Protonation of both metal centers in [{Ir(mu-Pz)(CO)(2)}(2)] with HCl occurs at low temperature, but eventually the mononuclear compound [IrCl(HPz)(CO)(2)] is isolated. The related complex [{Ir(mu-Pz)(CO)(P{OPh}(3))}(2)] reacts with HCl and with HO2CCF3 to give the neutral Ir(III)/Ir(III) complexes [{Ir(mu-Pz)(H)(X)(CO)(P{OPh}(3))}(2)], respectively. Both reactions were found to take place stepwise, allowing the isolation of the intermediate monohydrides. They are of different natures, i.e., the metal-metal-bonded Ir(II)/Ir(II) compound [(P{OPh}(3))(CO)(Cl)Ir(mu-Pz)(2)Ir(H)(CO)(P{OPh}(3))] and the mixed-valence Ir(I)/Ir(Ill) complex [(P{OPh}(3))(CO)Ir(mu-Pz)(2)Ir(H)(eta(1)-O2CCF3)(CO)(P{OPh}(3))].