Two new and six previously known coumarin derivatives with promising biological properties were synthesized in moderate to good yields by reaction of 4-chloro-3-nitro-coumarin and the appropriate arylamine in ethyl acetate in the presence of triethylamine. The synthesized compounds were evaluated for their in vitro antibacterial and antifungal activities against pathogenic strains. A correlation between the aryl substituent identity and antimicrobial activity was discussed.