(E)- and (Z)-5-(Bromomethylene)furan-2(5H)-ones and (E)- and (Z)-3-(bromomethylene)isobenzofuran-1(3H)-ones have been prepared starting from commercially available maleic anhydrides and phthalic anhydrides, respectively. A debrominative decarboxylation or a bromodecarboxylation reaction is a key step in the synthesis. The furanones were investigated for their ability to interfere with microbial communication and biofilm formation by Staphylococcus epidermidis.