This paper describes the grafting of 1,10-phenanthroline (P) molecules on the surface of a glassy carbon (GC) electrode. This modification was carried out in both aqueous and non-aqueous media. Britton Robinson (BR) was used in aqueous experiments at different pHs and tetrabutylammonium tetrafluoroborate (TBATFB), 0.1 M in acetonitrile (ACN) was used in non-aqueous experiments. Surface modification experiments were performed in the +1.2-2.7 V potential range with a scan rate of 100 mV/s and 30 cycles. The presence of P at the GC surface was characterized by cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), contact angle measurement (CAM) and ellipsometry. The ability of the complex to modify surfaces was investigated with differential pulse voltammetry (DPV). Crown Copyright © 2009.