In an effort to provide precedence for postulated intermediates in copper-protein-mediated nitrite reduction, a series of novel complexes containing the Cu I -NO 2 -unit, including monocopper(I), dicopper(I,I), and mixed valence dicopper(I,II) and copper(I)-zinc(II) species, were prepared, fully characterized, and subjected to reactivity studies designed to probe their ability to produce nitric oxide. Treatment of solutions of [LCu(CH 3 CN)]PF 6 (L ) L i-Pr 3 , 1,4,7-triisopropyl-1,4,7-triazacyclononane, or L Bn 3 , 1,4,7-tribenzyl-1,4,7-triazacyclononane) in MeOH with excess NaNO 2 yielded the novel dicopper(I,I) complexes [(LCu) 2 (µ-NO 2 )]PF 6 . The complex with L ) L i-Pr 3 was cleaved by PPh 3 to afford [L i-Pr 3 Cu(PPh 3 )]PF 6 and L i-Pr 3 Cu(NO 2 ), a structural model for the substrate adduct of copper nitrite reductase. Oxidation of the dicopper(I,I) compound (L ) L i-Pr 3 ) with (Cp 2 Fe)(PF 6 ) in CH 2 Cl 2 yielded the deep red, mixed valent, dicopper(I,II) species [(L i-Pr 3 Cu) 2 (µ-NO 2 )](PF 6 ) 2 , which was structurally characterized as its [B(3,5-(CF 3 ) 2 C 6 H 3 ) 4 ] -salt (crystal data: triclinic space group P1 h, a ) 13.439(8) Å, b ) 13.777(5) Å, c ) 14.471(8) Å, R ) 108.22(4)°, β ) 92.08(5)°, γ ) 90.08(4)°, Z ) 1, T ) 177 K, R ) 0.074, and R w ) 0.070). A diamagnetic heterodinuclear Cu I Zn II analog, [L i-Pr 3 Cu(µ-NO 2 )ZnL i-Pr 3 ](O 3 SCF 3 ) 2 , was assembled by mixing L i-Pr 3 Cu(NO 2 ), Zn(O 3 -SCF 3 ) 2 , and L i-Pr 3 and was shown to adopt a structure similar to that of its Cu I Cu II relative (crystal data: monoclinic space group P2 1 /c, a ) 10.8752(1) Å, b ) 15.6121(3) Å, c ) 25.8020(5) Å, β ) 90.094(1)°, Z ) 4, R1 ) 0.0472, and wR2 ) 0.1082). Both compounds exhibit an intense electronic absorption feature that was assigned as a Cu I f NO 2 -MLCT transition on the basis of resonance Raman spectroscopic results.