Department of Chemistry, Faculty of Science, Al-Azhar University, Nasr-City, Cairo, A. B. Egypt Manuscript received 19 June 1982, accepted 23 April 1983 The synthesis of different 3-(2-carbonyldibenzothiophene)propanoylamino acid methyl esters (IV-VIII), 3-(8-nitro-2-carbonyldibenzothiophene)propanoylamino acid methyl esters (XIX-XXIII) and 3-(8-nitro-2-carbonyldibenzothiophene-5,5-dioxide)propanoylamino acid methyl esters (XXXI-XXXV), corresponding hydrazides and some dipeptide methyl ester derivatives (IV-XLIII) have been achieved employing the carbodiimide and azide methods. Amongst the compounds synthesized, nine of various 2- and 8-substituted dibenzothiophene propanoylamino acid derivatives (IV, VII, X, XX, XXIII, XXVII, XXXI, XXXII and XXXV) were found to possess antimicrobial activities towards different microorganisms.