D-Mannono-1,4-lactone is primarily used in the field of organic synthesis as a key intermediate for producing various bioactive compounds. It plays a significant role in the preparation of chiral building blocks, which are essential for synthesizing pharmaceuticals, particularly those targeting glycosidase enzymes. This compound is also utilized in the development of carbohydrate-based drugs and glycoconjugates, which are important in cancer therapy and immunology. Additionally, it finds application in the food industry as a precursor for producing certain food additives and sweeteners. Its ability to act as a chelating agent makes it useful in water treatment processes for binding metal ions.