To get insight into the relevance of targeting hemozoin (Hz) crystals, two isomeric series, N5, N10-bis-alkylamine (2a–k) and N10, O11-bis-alkylamine (3a–k) indolo [3, 2-b] quinolines, were evaluated for their in vitro activity against chloroquine (CQ)-resistant and sensitive strains of Plasmodium falciparum. In general, compounds of series 3 were more active than isomers 2, with IC50/LD50 ranging from 25/233 nM (3i) to 1.3 (3a)/10.7 (3b) μM. SAR ...