The study of the Vilsmeier–Haack reagent on 4-hydroxyquinaldines resulted in a new versatile intermediate 4-chloro-3-formyl-2-(2-hydroxy-ethene-1-yl) quinolines, which on further treatment with hydrazine hydrate yielded the desired diazepino quinoline derivatives. All the synthesized diazepino quinoline derivatives are screened for their antibacterial and antifungal activities. Cytogenetic analysis of the samples is also reported.