A new series of aryl substituted ketene dithioacetals 6a–h was synthesized and evaluated for their in vitro and in vivo antileishmanial activity against Leishmania donovani. Two compounds exhibited significant in vitro activity against intracellular amastigotes of L. donovani with IC50 values 3.56 and 5.12 μM and were found promising as compared with reference drug, miltefosine. On the basis of good