CuGaO₂ is used here as photocathode in place of NiO for a p-type dye-sensitized solar cell with iodide/triiodide (I⁻/I₃ ⁻) or tris(4,4′-bis-tert-butyl-2,2′-bipyridine)cobalt (Co²⁺/Co³⁺) as redox mediator, and PMI or PMI-NDI as sensitizer. Both photovoltaic characteristics and flat band potentials suggest that CuGaO₂ can be viewed as a promising substitute for NiO.