Abstarct: Heterocyclic compounds containing quinoxaline unit have a wide variety of biological activities. In this work, new derivatives of furo/thieno[2,3-b]quinoxaline were prepared by the Pd-catalyzed coupling reactions (Heck reaction and Sonogashira coupling). For the synthesis of furo/thieno[2,3-b]quinoxalines, first, the starting materials 2-methoxy-3-(phenylethynyl)quinoxaline and 2-(methylthio)-3-(phenylethynyl) quinoxaline were prepared by the coupling reaction of 2-chloro-3-methoxyquinoxaline and 2-chloro-3-(methylthio)quinoxaline with terminal alkynes. In continue, the iodocyclization of the resulting compounds afforded 3-iodo-2-phenylfuro[2,3-b]quinoxaline and 3-iodo-2-phenylthieno[2,3-b] quinoxaline. The subsequent palladium-catalyzed Sonogashira, Suzuki, and Heck reactions of the resulting iodo-compounds led to the formation of 2,3-disubstituded furo/thieno[2,3-b]quinoxalines in high yields. The synthesized quinoxaline compounds were also screened against the two bacterial strains. Pyrrolo[2,3-b]quinoxalines substituted at the 2 and 3 positions by an aryl, acyl or alkyl group were readily prepared by the reaction of 3-chloroquinoxalin-2-amines with internal alkynes and also, by the reaction of 3-chloroquinoxalin-2-amines with chalcones. These reactions catalyzed by Pd(OAc)2 in the presence of KOt-Bu, as the baxse and NaOAc, as the additive in DMSO afforded the desired products in high yields. The MIC and MBC determination reveal that these compounds can be used for the development of antibiotics in the future.