Antileishmanial agent-27 (compound 7j) is a benzothiazolo-coumarin derivative. Antileishmanial agent-27 is a competitive inhibitor of arginyl-tRNA synthetases (ArgRSs). Antileishmanial agent-27 shows selectivity toward ArgRS of Leishmania donovani ( Ld ArgRS) than its human counterpart (HsArgRS), with IC 50 values of 1.2 and 19 μM, respectively. Antileishmanial agent-27 possesses high pharmacokinetic properties.