Dienone

Dibenzylideneacetone is a well known dienone

A dienone is a class of organic compounds with the general formula (R2C=CR)2C=O, where R is any substituent, but often H. They are formally "derived from 1,4-diene compounds by conversion of a –CH2– group into –C(=O)– group", resulting in "a conjugated structure". They are a kind of enone. The class includes some heterocyclic compounds.