A bifunctional phenylene ether oligomer containing monophenylene and biphenylene moieties can be rendered thermosetting by reacting the terminal phenolic hydroxyl groups with a) a cyanogen halide to introduce terminal cyanate groups, b) a halogenated glycidyl to form terminal epoxy groups, or c) an allyl halide to produce allylic terminal groups. The epoxy-terminated phenylene ether oligomer can be further reacted acrylic and/or methacrylic acid to yield an epoxy di(meth)acrylate which can be further modified with a carboxylic acid or anhydride to obtain and acid-modified epoxy di(meth)acrylate.