Optical brightener is a kind of fluorescent dye and also known as white dye. It can excite incident ray to produce fluorescence, which can bring bright white effect to dyed substance, and it is classified as color conditioner. It is a fine chemical product in granular from with yellowish shade. Without toxic, is not irritating to human skin, is not harmful to human health, is not harmful to ecological environment and has no side effect on human health.

There are wide range of applications for optical brighteners. In the 1940s, A German company Bayer took the lead in realizing the industrialized production of fluorescent whitening agents. Since then, the production and application of optical brighteners have gradually expanded all over the world.

According to chemical structure, optical brighteners mainly include coumarin type, stilbene type, phthalimide type, pyrazoline type, benzoxazole type, bistriazine type, and other types. Among all these types, the stilbene type has blue fluorescence and has the biggest share in global production and sales. The stilbene based optical brightener is widely used in the European Union, United States, Japan, China and other countries.

Optical brighteners are applied in the processing and production of synthetic fibers, cotton fibers, paper, detergent, plastics, and other products. Also, optical brighteners are used in anti-counterfeiting printing, high-sensitivity films ,fluorescent detection, and other fields.The main application areas of optical brighteners are daily chemicals and detergents, which is 41% of the demand; followed by other chemical industries such as plastics and paper, which is around 32%; followed by leather, and other textile which is around 20% of the demand; left 7% is relatively small for other industries.

Optical brighteners have very rapid development. And together with reactive dyes and DDP organic pigments, they become three major achievements in dye industry in late 20th century.