A novel copper(I) complex bearing two 6,6′-dimethyl-2,2′-bipyridine-4,4′-dibenzoic acid ligands was prepared along with related deprotonated derivatives. Their performance as photosensitizer in DSSCs was studied as a function of the anchoring group and the electrolyte composition, comparing it with that of a copper(I) complex bearing two 6,6′-dimethyl-2,2′-bipyridine-4,4′-dicarboxylic acid ligands and N719.•A new Cu(I) complex with 6,6′-dimethyl-2,2′-bipyridine-4,4′-dibenzoic acid ligands.•Best power conversion efficiency (3.0%) for a DSSC based on a Cu(I) complex.•Effect of the nature of the electrolyte on the efficiency of DSSCs based on Cu(I) dyes.