Disclosed herein are antibacterial compounds that inhibit fabl, a NADH-dependent enoyl [acyl carrier protein] reductase enzyme in the fatty acid biosynthesis pathway. The compounds are represented by structural formulas Ia and Ib: R1 and R2 are independently monocyclic aryl or heteroaryl groups, wherein the groups represented by R1 and R2 are optionally substituted with one or more acyclic substituents; R3 is —H or an optionally substituted C1-C8 aliphatic, C3-C8 cycloaliphatic, aryl, or heteroaryl group. X1 is a bond or a C1-C3 alkylene chain that is optionally substituted with a C1-C4 alkyl or an acidic group. X2 is an aryl, heteroaryl or C3-C8 cycloaliphatic ring, wherein the group represented by X2 is optionally substituted with triazole, tetrazole, and/or one or more acyclic substituents.