Abstract A preliminary in vitro screening of compounds belonging to various chemical families from our library revealed the thieno [3, 2-d] pyrimidin-4 (3H)-one scaffold displayed a promising profile against Plasmodium falciparum. Then, 120 new derivatives were synthesized and evaluated in vitro; compared to drug references, 40 showed good activity toward chloroquine sensitive (IC 50 35–344 nM) and resistant (IC 50 45–800 nM) P. ...