The obtained crystals were suitable for single-crystal X-ray crystallography. These copper complexes crystallize in the triclinic system with a P-1 space group. The three compounds show similar distances between the metal center and the central nitrogen atom of the triazole unit (2.063 Å for 26a, 2.060 Å for 26b, 2.067 Å for 26c), while the distance between the copper and the nitrogen atom of the quinoxaline ring is slightly smaller for 26a (2.061 Å) than the ones of 26b