The present work involved preparation of diaromatic heterocyclic compounds The first step involved preparation of 2-substitution butyl benzoate (1-4), second step preparation of 2-substitution benz acid hydrazide (5-8),then preparation of dioxadiazole (9-12) from the reaction of two molecules of 2-substitution benz acid hydrazide with adipoyl chloride in the present triethylamine as catalyst. All the prepared compounds in this work were characterized by melting points with other physical properties, infrared (FTIR) and 1H-NMR, 13C-NMR spectra Screening microbial activity of the preparation dioxadiazole compounds were evolution against two types of (Gram positive).