A hypothetical heterocyclic compound of formula C9H9N, whose molecule contains two six-membered rings sharing a nitrogen and a carbon atom; any of numerous (known) compounds whose molecules contain such a ring system in substituted or combined form.
A number of isomeric structures are possible for C9H9N..
Origin
Early 20th century; earliest use found in Journal of the Chemical Society. From quinoline with inserted iz- (representing azo-), after German Chinolizin.