A series of 1, 3, 5-trisubstituted pyrazolines were synthesized and evaluated for in vitro antimalarial efficacy against chloroquine sensitive (MRC-02) as well as chloroquine resistant (RKL9) strains of Plasmodium falciparum. The activity was at nano molar concentration. β-hematin formation inhibition activity (BHIA50) of the pyrazolines were determined and correlated with antimalarial activity. A reasonably good correlation (r= ...