Fine chemicals are pure, some chemicals are commercially produced by chemical reactions in highly specialized applications. Fine chemicals produced can be divided into active pharmaceutical ingredients and their intermediates, biocides and specialty chemicals for technical applications.

In chemical engineering, is a distinction between bulk chemicals produced in large quantities by standard reactions, and fine chemicals, which are custom manufactured in smaller quantities for special applications. There is a very large number of fine chemicals that are produced, and thus chemistry for the production of these need to be flexible while the atom economy is not as critical as for bulk chemicals. The small size and often-changing chemicals, fine chemicals production is expensive, generates more waste and require a greater investment in research per kilogram. However, fine chemicals produced in industrial quantities, unlike the research chemicals that can only be produced in the laboratory.

With the introduction of new drugs to market, the chemical identity of pharmaceuticals and their intermediates change often, and they are also produced in small quantities, thus being fine chemicals. Active pharmaceutical ingredients are formulated in a separate factory, where they are mixed with inert pigments, solvents and additives, and made into dosage forms. Fine chemicals manufacture of pharmaceutical products and intermediates needs to meet strict standards of Good Manufacturing Practice, and is controlled by the Food and Drug authorities, notably the U.S. Food and Drug Administration (FDA).

Biocides are pesticides, herbicides and other specialty chemicals used in agriculture to inhibit or kill pests and weeds and thus improve revenues. New biocides have developed more slowly than new drugs.

Special chemicals are produced for technical applications. Inks, performance-enhancing additives, special coatings, and photographic chemicals are known examples. They are generally sold based on differentiated performance characteristics in use instead of the price per mass, the basis for the fine chemicals are generally sold.