The water oxidation reaction (WOR) is one of the most important reactions on the planet since it is the source of nearly all the atmosphere's oxygen. Understanding its intricacies can hold the key to improve the efficiency of the reaction. Unfortunately, the reaction's mechanisms are complex and the intermediates highly unstable, thus making their isolation and characterisation extremely challenging. To overcome this, scientists are using molecular catalysts as models to understand the fundamental aspects of water oxidation—particularly the oxygen-oxygen bond-forming reaction.