The reaction of imines with alkynes and alkenes, in the presence of 2,3-dichloro-5,6-dicyano-p-benzoquinone (DDQ), to give quinoline derivatives is described. The mechanism of the annulation is discussed, and evidence supporting a non-concerted pathway, at least when the alkene is butyl vinyl ether, is reported. Preliminary information is also given about solid adducts of imines with DDQ, which do