context: In an another set of experiments, the DPP dyes 1 and 2 were cross-linked with 3 with the classical copper-catalyzed protocol by heating the photoelectrode for 10 minutes at 30 °C in a DMF solution with Cu(SO4)·5H2O, sodium ascorbate in presence of the tris(benzyltriazolylmethyl)amine (TBTA) ligand. The completion of the reaction was confirmed by the ATR-IR spectroscopy (Fig. S25 and S26†). The results of the photovoltaic performances of the solar cells made with the I3−/I− redox couple are gathered in Table S3.† Clearly, the conditions of copper catalyzed Huisgen cycloaddition, although conducted in mild conditions, negatively impact the performances of the solar cells since the PCEs are notably lower than those measured with the thermal crosslinking activation. For TiO2 based solar cells, both Jsc and Voc were diminished upon cross-linking. Interestingly, the performances of photocathodes with NiO are less degraded than those with the photoanodes based on TiO2, because only the Jsc was decreased after copper-catalyzed cross-linking. This result is consistent with the upward shift of the valence band of NiO upon insertion of copper cation into the lattice as it was previously reported. Another possibility, is the presence of remaining Cu(II) salt, which is a paramagnetic metal that could quench the excited state of the dye and consequently diminishes the charge injection quantum yield as shown by Hanson and co-workers.