4,6-Dimethoxyhomophthalic acid (
5) has been synthesized efficiently in four steps from 3,5-dimethoxycinnamic acid (
1) and characterized and screened for their in vitro antibacterial activity against four Gram negative (
Escherichia coli, Pseudomonas aeruginosa, Salmonella typhii, and Shigella flexneri) and two Gram-positive (
Bacillus subtilis and Staphylococcus aureus) bacterial strains, and for in vitro antifungal activity against
Trichophyton longifusus, Candida albicans, Aspergillus flavus, Microsporum canis, Fusarium solani, and Candida glaberata. The compounds were screened for their in vitro antiherbicidal and antifungicidal activities.