¹Istanbul University, Faculty of Pharmacy, Department of Pharmaceutical Chemistry, 34116 Istanbul, Turkey DOI : 10.12991/marupj.259887 New N"-(arylidene)-2-[6-(4-bromophenyl)imidazo[2,1-b] thiazol-3-yl]acetohydrazides (3a-i) were synthesized by reacting 2-[6-(4-bromophenyl)imidazo[2,1-b]thiazol-3-yl] acetohydrazide with different aromatic aldehydes. The structures of the title compounds were established by spectral data (IR, 1H NMR, 13C NMR) and elemental analyses. The synthesized compounds were evaluated for in vitro antimycobacterial activity against Mycobacterium tuberculosis H37Rv employing the BACTEC 460 radiometric system. The compounds exhibited varying degrees of inhibition in the in vitro primary screening that was conducted at a concentration of 6.25 mg/ml. Among the synthesized compounds [6-(4-bromophenyl)imidazo[2,1-b] thiazol-3-yl]acetic acid 2,4-dinitrobenzylidenehydrazide (3e) was found to be the most active compound in vitro with MIC of 6.25 mg/ml. Keywords : Imidazo[2,1-b]thiazole, hydrazone, antimycobacterial activity