A series of new benzocoumarin amino acid derivatives were synthesized with the aim of evaluating their antimicrobial activity. Their chemical structures were confirmed by 1H-NMR and mass spectrometry. The antimicrobial activity was screened on two types of bacteria S. aureus and E. coli besides, two types of fungi Alternari brassicicola and Fusarium oxysporum. Out of the eleven tested compounds, two derivatives benzo [5,6] coumarin-3-carboxylic acid 1 and Benzo [5,6] coumarine-3-carboxyl DL- threonine methyl ester 4c exhibited good activity at 1000 ppm against Gram-positive bacteria S. aureus especially compound 1 which has an activity greater than that of the reference drug (Gentamicin ®).