Roh and coworkers reported a series of 3,5-dinitrobenzylsulfanyl-1,3,4-oxadiazoles and thiadiazoles derivatives with potent activity against replicating and nonreplicating Mycobacterium tuberculosis. Compounds (1) and (2) (Figure 1) were the most promising in this series and presented MIC90 values against several MDR strains below 0.25 μM. Moreover, these compounds have been shown to be active against dormant mycobacteria using a luciferase assay. In vitro cytotoxicity studies against mammalian cell lines and isolated human hepatocytes showed low toxicity with inhibitory concentration (IC50) values above 20 μM. Both compounds also did not exhibit mutagenic activity and activity against several bacteria and fungi. Furthermore, studies were performed which attempted to characterize the possible target of the compounds. In vitro studies suggested that compounds (1) and (2) could act inhibiting the synthesis of nucleic acids . The same research group has reported a new series of 3,5-dinitrophenyl 1,3,4-oxadiazole-2-thiols and tetrazole-5-thiols as promising antitubercular agents. They have discovered compounds (3) and (4) (Figure 1) as highly potent and selective derivatives against seven MDR and XDR strains with MIC90 values below 0.5 μM. In addition, these compounds exhibited low cytotoxicity against human hepatocellular carcinoma (HuH7), human epidermoid carcinoma (A431), Madin-Darby canine kidney cells (MDCK), human hepatocellular carcinoma (HepG2) cell lines, with IC50 above 30 μM .