A new method for the synthesis of quinolines has been developed by employing various novel catalysts such as Al(OTf)3, Gd(OTf)3, and TMSCl-NaI. Later, these compounds were condensed with 3-hydrazino benzothiadiazines to obtain quinoline derived [1,2,4]triazolo[1,5-b][1,2,4] benzothiadiazines. Further, these new molecules have been evaluated for their antibacterial activity and some of them have exhibited significant antibacterial activity in comparison to sulfadiazine. Keywords: Quinolines, Benzothiadiazines, Al(OTf)3, Friedlander synthesis, TMSCl-NaI, One-pot method, Triazolobenzothiadiazine, Antibacterial activity