Antimicrobial compositions of bromonitrostyrene or system comprising propylene carbonate, ethylene carbonate bromonitroethenylfuran are formed in a carrier solvent or mixtures thereof. The propylene carbonate system may additionally include tetrahydrofurfuryl alcohol. The compositions have good activity and stability, are non-toxic, non-flammable, non-corrosive, odorless, and colorless, and have desirable boiling and flash points and vapor pressure.