Cyclopent-4-ene-1,3-dione is a highly reactive cyclic diketone organic compound that has been employed as a key synthetic intermediate in the laboratory synthesis of more complex molecules, including 2-methoxymethylene-Cyclopent-4-ene-1,3-dione and the natural product derivative chrysotrione B (a 2-acylcyclopentene-1,3-dione derivative), Cyclopent-4-ene-1,3-dione was historically used to investigate the influence of sulfhydryl group-specific chemical reagents on the activity of bovine heart phospholipid exchange protein.