Acenaphthene is a [[/wiki/Polycyclic_aromatic_hydrocarbon|polycyclic aromatic hydrocarbon]] (PAH) consisting of [[/wiki/Naphthalene|naphthalene]] with an [[/wiki/Ethylene|ethylene]] bridge connecting positions 1 and 8. An alternative name, 1,2-dihydroacenaphthylene, emphasizes that it is a hydrogenated form of [[/wiki/Acenaphthylene|acenaphthylene]]. It is a constituent of [[/wiki/Coal_tar|coal tar]].
Acenaphthene was prepared the first time from coal tar by [[/wiki/Marcellin_Berthelot|Marcellin Berthelot]] and after that with Bardy he synthesized it from α-ethyl naphthalene.
It is used in preparation of dyes, pesticides and pharmaceuticals.
It does not appear to be [[/wiki/Carcinogenic|carcinogenic]].