(Z)-Stilbene is a diarylethene, that is, a hydrocarbon consisting of a cis ethene double bond substituted with a phenyl group on both carbon atoms of the double bond. The name stilbene was derived from the Greek word stilbos, which means shining.

Stilbene exists as two possible isomers known as (E)-stilbene and (Z)-stilbene. (Z)-Stilbene is sterically hindered and less stable because the steric interactions force the aromatic rings 43° out-of-plane and prevent conjugation.^[2] (Z)-Stilbene has a melting point of 5–6 °C (41–43 °F), while (E)-stilbene melts around 125 °C (257 °F), illustrating that the two compounds are quite different.

• Stilbene is used in manufacture of dyes and optical brighteners, and also as a phosphor and a scintillator.
• Stilbene is one of the gain mediums used in dye lasers.

• Stilbene will typically have the chemistry of a diarylethene, a conjugated alkene.
• Stilbene can undergo photoisomerization under the influence of UV light.
• Stilbene can undergo stilbene photocyclization, an intramolecular reaction.
• (Z)-Stilbene can undergo electrocyclic reactions.
• In strong (protic) acid, cis-stilbene oligomerizes to a phenylmethylene chain capped by diphenylindane groups. The analogous trans compound doees not so react.^[3]

Many stilbene derivatives (stilbenoids) are present naturally in plants. An example is resveratrol and its cousin, pterostilbene.