Because of the increasing demand for energy worldwide and global warming, the development of renewable energy sources is required to enable reduced consumption of fossil fuels. In the field of solar-energy conversion into electricity, dye-sensitized solar cells (DSCs) have attracted considerable attention owing to their low cost and high efficiency.1 DSCs based on ruthenium sensitizers have reached overall solar-to-electric power-conversion efficiency (PCE) of 11.4 % under standard air mass 1.5 G illumination.2–6 For reasons of availability and cost, it is important to develop efficient noble-metal-free sensitizers. Much effort has been devoted to the development of donor–π-acceptor (D–π-A) organic sensitizers, which currently reach more than 10 % PCE.7–11 Porphyrins have drawn much attention as sensitizers as a result of the large absorption coefficients of their Soret and Q-bands in the visible region. It is possible to tune the spectral properties and energetics of porphyrins by functionalization at the meso and β positions of the chromophore.12–19 The strategy of introducing donor and acceptor moieties at the periphery and using a zinc porphyrin chromophore as a π bridge has produced a whole new family of efficient sensitizers by creating judicious directional electron flow from the donor to the acceptor moiety, which anchors the dye to the surface of the oxide scaffold acting as the electron acceptor.20–25 Recently, a PCE of 12.3 % was reached by combining a donor–acceptor zinc porphyrin with an organic cosensitizer dye and using a cobalt complex as a redox shuttle in the electrolyte.26 The cosensitization approach is effective in promoting a broad absorption spectral response; the device performance is enhanced through the application of two dyes containing complimentary absorption spectra. Previously