Carbon fibre pre-impregnated tape (prepreg) was prepared from a range of prepolymers comprising blends of propenyl-functionalized cyanate ester (CE) oligomers with commercial bis-maleimide (BMI) monomers. Cured neat resin plaques and carbon fibre composites were prepared by autoclave moulding. Various blends of a commercial BMI mixture, a CE and a co-monomer with either allyl or propenyl and cyanate pendant groups were prepared. Differential scanning calorimetry (d.s.c.) data were used to monitor cure of neat resin, while dynamic mechanical thermal analysis (d.m.t.a.) was used to assess cure cycles of composite materials by the measurement of glass transition temperatures (T-g). Composite properties measured were interlaminar shear strength, flexural strength, compressive strength and Mode 1 Fracture toughness (G(IC)).