Dye-sensitized photocatalytic systems (DSPs) have been extensively investigated for solar-driven hydrogen (H2) evolution. However, their application in carbon dioxide (CO2) reduction remains limited. Furthermore, current solar-driven CO2-to-CO DSPs typically employ rhenium complexes as catalysts. In this study, we have developed DSPs that incorporate noble metal-free components, specifically a zinc-porphyrin as photosensitizer (PS) and a cobalt-quaterpyridine as catalyst (CAT). Taking a significant stride forward, we have achieved an antenna effect for the first time in CO2-to-CO DSPs by introducing a Bodipy as an additional chromophore to enhance light harvesting efficiency. The energy transfer from Bodipy to zinc porphyrin resulted in remarkable stability (turn over number (TON)=759 vs. CAT), and high CO evolution activity (42?mmol?g?1?h?1 vs. CAT).

A large number of multipolar dyes undergo excited-state symmetry breaking (ESSB) in polar media. During this process, electronic excitation, initially distributed evenly over the molecule, localizes, at least partially, on one donor–acceptor branch. To resolve its initial stage, ESSB is investigated with a donor–acceptor–donor dye in binary mixtures of nonpolar and polar solvents using time-resolved infrared absorption spectroscopy. The presence of a few polar molecules around the dye is sufficient to initiate ESSB. Although the extent of asymmetry in a mixture is close to that in a pure solvent of similar polarity, the dynamics are slower and involve translational diffusion. However, preferential solvation in the mixtures leads to a larger local polarity. Furthermore, inhomogeneous broadening of the S1 <- S0 absorption band of the dye is observed in the mixtures, allowing for a photoselection of solutes with different local environments and ESSB dynamics.