Influencing factors, including organic reductant, counterion of copper(II)–bipyridine complex, reaction solvent, molar ratio of copper(II)–bipyridine complex and organic reductant, reaction time and chelating ligand of copper complex, have been extensively investigated on the reaction of copper(II)–bipyridine complex mediated C–C bond cleavage of acetonitrile. Furthermore, in situ formation of a series of cyano-bridged mixed-valent copper complexes has been described in this paper, where twelve new copper complexes with or without the presence of cyanide anions have been yielded and structurally characterized including two novel one-dimensional (1D) mixed-valent copper coordination polymers. In addition, a trinuclear cyano-bridged mixed-valent copper complex 9, which is believed to be the most stable species in this system, shows effective activity in catalyzing Ullmann C–N cross-coupling reactions.