Dypnone or 1,3-Diphenyl-2-buten-1-one, (FR-0508, CAS 495-45-4), is formed by the condensation of two molecules of acetophenone under various catalysts. It is readily available from Frinton Laboratories, Inc. in small to medium quantities.

It is a yellow, dense liquid boiling at about 170°C at 3 mm.  Dypnone is mostly in E-configuration around the double bond. Dypnone (1,3-diphenyl-2-buten-1-one) is a useful intermediate for the production of a large range of compounds such as pyrroles and pyrimidines. It is useful in the synthesis of various symmetrical and asymmetrical 1,3,5-triaryl benzenes. Dypnone has also been used as a softening agent, plasticizer for vinyl resins, ultraviolet absorber in coatings and as a perfumery base.