Chanel No. 5 was the first perfume launched by French couturier Gabrielle "Coco" Chanel in 1921. The scent formula for the fragrance was compounded by French-Russian chemist and perfumer Ernest Beaux. The design of its bottle has been an important part of the product's branding. Coco Chanel was the first face of the fragrance, appearing in the advertisement published by Harper's Bazaar in 1937.

Perfume is a mixture of fragrant essential oils or aroma compounds (fragrances), fixatives and solvents, usually in liquid form, used to give the human body, animals, food, objects, and living-spaces an agreeable scent. Perfumes can be defined as substances that emit and diffuse a pleasant and fragrant odor. They consist of manmade mixtures of aromatic chemicals and essential oils. The 1939 Nobel Laureate for Chemistry, Leopold Ružička stated in 1945 that "right from the earliest days of scientific chemistry up to the present time, perfumes have substantially contributed to the development of organic chemistry as regards methods, systematic classification, and theory."