Cu2+/1+complexes facilitate the reduction of CO2to valuable chemicals. The catalytic conversion likely involves the binding of CO2and/or reduction intermediates to Cu2+/1+, which in turn could be influenced by the electron density on the Cu2+/1+ion. Herein we investigated whether modulating the redox potential of Cu2+/1+complexes by changing their ligand structures influenced their CO2reduction performance significantly. We synthesised new heteroleptic Cu2/1+complexes, and for the first time, studied a (Cu-bis(8-quinolinolato) complex, covering a Cu2+/1+redox potential range of 1.3 V. We have found that the redox potential influenced the Faradaic efficiency of CO2reduction to CO. However, no correlation between the redox potential and the Faradaic efficiency for methane was found. The lack of correlation could be attributed to the presence of a Cu-complex-derived catalyst deposited on the electrodes leading to a heterogeneous catalytic mechanism, which is controlled by the structure of the in situ deposited catalyst and not the redox potential of the pre-cursor Cu2+/1+complexes.