Abstract: Monoallyloxyimides, diallyloxyimides and polyallyloxyimides of general Formula I. ##STR1## wherein: X is an integer from 1 to 4 inclusive;R.sup.1, R.sup.2, and R.sup.3 are independently selected from the group comprising hydrogen, alkyl, arylalkyl or halogen; andA is all or part of an aromatic, alicyclic or mixed aromatic/alicyclic ring system optionally substituted with one or more alkyl, alkoxy, alkylthio, aryl, heteroaryl, aryloxy, carboxy, alkylamino, dialkylamino, amino, nitro, cyano, halo or haloalkyl groups.This new class of reactive monomer can be used as co-reactants in themosetting matrix resins. The reactive monomers, either alone or with other comonomers, can give rise to cured resin matrix materials with high thermal stability. Mixed with suitable bismaleimide monomers, they can be cured into useful composites having substantially improved thermal stabilities.