Condensation of carbohydrazide derivatives Ia, b with dimethyl acetylenedicarboxylate and acetylenedicarboxylic acid yielded benzofuran derivatives II a-d. Reaction of Ib with aromatic aldehydes formed products III a-d. Treatment of compounds III a-d with mercaptoacetic acid yielded the cyclocondensation products (IVa-d). Phthalic anhydride reacted with compounds (Ia, b)to form products (Va, b). It has been found that both khellin and visnagin (VIa, b)react with aromatic aldehydes to give arylidene derivatives (VIIa-e). Condensation of diphenyl nitrilamine with 2-arylidene furochromones VII derivatives afforded cyclo-adducts (VIII a-i). The antibacterial activities of the selected compounds were tested against Staphylococcus aureus, B. subtilis, E. coli, Pseudomonas, Salmonella and Erwinia with good results.