A low melting citric acid‐urea mixture was found to be a new and effective promoting medium for the environmentally friendly synthesis of 1,8‐dioxo‐dodecahydroxanthene derivatives by condensation of aromatic aldehydes and cyclic 1,3‐dicarbobonyl compounds. This deep eutectic solvent acts as both the reaction medium and catalyst, furnishing xanthenediones in high to excellent yields.