A new series of N-arylamino biquinoline derivatives 5a-x were synthesized by reaction of 2-chloro-3-formyl quinolines 2a-d with malononitrile and various enhydrazinoketones 4a-f in absolute ethanol. The newly synthesized compounds were evaluated for their in vitro antimicrobial activity against a representative panel of pathogenic strains and antituberculosis activity against Mycobacterium tuberculosis H37Rv. Compounds 5h and 5s exhibited excellent antibacterial activity and some of the compounds demonstrated moderate antituberculosis activities compared with the first line drugs. The compounds were evaluated in vitro for their activity against the growth of Plasmodium falciparum, the malaria causing parasite. Some of them showed antimalarial activity with IC(50) values as low as 0.005-0.009 μg/mL.