Photochemical reactions in which cobalt(II) complexes catalyze the hydrogen evolution reaction (HER) in aqueous solution has been studied by time-resolved spectroscopy and computational modeling. More information can be found in the Research Article by P. Persson, J. Lloret-Fillol, B. Dietzek-Ivanšić, E. Nordlander and co-workers (DOI: 10.1002/chem.202582801). Cover illustration created by Iria Bolaño Losada. Link: https://chemistry-europe.onlinelibrary.wiley.com/toc/15213765/2025/31/28