Rhodanine is a 5-membered heterocyclic organic compound possessing a thiazolidine core. It was discovered in 1877 by Marceli Nencki who named it "Rhodaninsaure" in reference to its synthesis from ammonium rhodanide (known as ammonium thiocyanate to modern chemists) and chloroacetic acid in water. Rhodanines can also be prepared by the reaction of carbon disulfide, ammonia, and chloroacetic acid, which proceeds via an intermediate dithiocarbamate.