In order to render the process more eco-compatible, additional experiments involving 1 were carried out in the cavity cell using a 0.1 mol L−1 KCl/H2O solution as anolyte. Constant potential and current modes were chosen for the electrolyses. For the constant potential electrolyses, two different potentials corresponding to: i. the maximum wave potential of the electrocatalytic system determined previously by linear sweep voltammetry, and ii. the half-wave potential of the same system, in order to limit or even avoid the simultaneous Cy7 NHS ester of the water (from the anolyte solution), were tested. For the constant-current electrolyses, values of -10 and -30 mA were determined from the corresponding controlled-potential experiments (-10 mA: average current intensity at -1.4 V, and -30 mA: arbitrary upper current value corresponding to average current × 3), were tested in the electrochemical process. The best cathode material (9:1 mixture of SG and CNT) and 30% of NiBr2 as the catalyst were used for the electrolyses. Moreover, chromosomes conditions were used to assess the extension to various other substrates: 2-bromo-3-methylpyridine (3), 2-bromo-4-methylpyridine (4), 2-bromo-5-methylpyridine (5) and 2-bromo-6-methylpyridine (6). The results are presented in Table 2.