Anew and efficient method has been used to synthesis of 2-chloro-1,8-naphthyridine carbaldehyde(1) from reaction of N-(pyridine-2-yl) acetamide in the presence of dimethylformamide and phosphorous oxychloride through Vilsmeir-Haack cyclization. The reaction of compound (1) with acetophenone, p-hydroxy acetophenone, pyridine-3-acetyl, furan-2-acetyl and indole-2-acetyl with ethanolic sodium hydroxide through Claisen-Schmidt condensation yield chalcones (2a-e) and them treated with dimethyl sulfoxide in the presence of 1,2-crystal of iodine to give iodochalconces (3a-e). Bromination of these chalcones affords dibromide (4a-e). IR and 1HNMR are used to identified the structure of these compounds: compound (2b,3b,3e,4a,4c) showed moderate activity to both gram positive and gram negative bacteria.