Two highly functionalized resins were synthesized by the phase transfer reaction of indene with propargyl bromide or allyl chloride in the presence of strong base. The resins consisted of a mixture of tri-and tetrafunctional indenes with 60-80% of the product being tetrafunctional. The allylated (AL) and propargylated (PL) indene resins were thermally cured without added catalysts. Both resins exhibited a broad, highly exothermic cure with a peak energy at 320 degrees C for AL resin and 282 degrees C for PL resin. Thermal degradation of cured AL resin was found to begin at approximately 400 degrees C with a carbon yield of 20% of its initial weight at 1000 degrees C. Carbon yields for cured PL resin were excellent, with 68% retention of weight at 1000 degrees C. Unidirectional, carbon fiber composites were fabricated from the substituted indene resins. AL-carbon fiber composites gave modulus values of 126 GPa and strength values of 967 MPa, while PL-carbon fiber composites gave modulus values of 116 GPa and strength values of 935 MPa in three-point bending tests.