There is an incessant interest in transfer of common chemical processes from organic solvents to water, which is vital for the development of bioinspired and green chemical technologies. Diarylethenes feature a rich photochemistry, including both irreversible and reversible reactions that are in demand in organic synthesis, materials chemistry, and photopharmacology. Herein, we introduce the first versatile class of diarylethenes, namely, potassium 2,3-diarylmaleates (DAMs), that show excellent solubility in water. DAMs obtained from highly available precursors feature a full spectrum of photoactivity in water and undergo irreversible reactions (oxidative cyclization to phenanthrenes or rearrangement) or reversible photocyclization (switching), depending on their structure. This finding paves a way towards wider application of DAEs in photopharmacology and bioinspired technologies that require aqueous media for photochemical reactions.