Chem. Sci., 2025, Accepted Manuscript DOI: 10.1039/D5SC04961J, Edge Article Giacomo Salvadori, Piermarco Saraceno, Alisia Santomieri, Chris John, Laura Pedraza Carotenoids serve as accessory light-harvesting pigments in microbial rhodopsins, but the mechanisms enabling efficient energy transfer in systems lacking canonical 4-keto groups remain poorly understood. Here, we combine long-timescale molecular...