Reaction of CuX (X=Cl, Br, I), PPh 3 and 2-(arylazo)pyridine, R-H 4 C 6 NNC 5 H 4 N (aap, 1 where R=H (pap), p-Me (p-tap), m-Me (m-tap)) has synthesized [Cu((aap)(PPh 3 )X]. The structure has been established by spectroscopic (UV–Vis, 1 H NMR) data and by single crystal X-ray diffraction of [Cu((pap)(PPh 3 )Br]. Addition of H 2 O 2 to [Cu((aap)(PPh 3 )Cl] has afforded blue Cu(II) complexes, [Cu(aapO)(PPh 3 )Cl]. These complexes have been characterized by elemental analyses, IR, UV–Vis spectral and magnetic data. Upon addition of H 2 S saturated dil. H 2 SO 4 solution to [Cu(aapO)(PPh 3 )Cl] free aapOH is separated and has been characterized by spectral data. Cyclic voltammogram of [Cu((aap)(PPh 3 )X] shows Cu(II)/Cu(I) response at 1.00–1.15V and azo reduction at negative to SCE. DFT calculation of optimized structure of a representative complex has been used to determine the composition and energy of molecular levels and data have been used to explain the electronic spectral and redox properties.