Abstract: Fumaric acid or a salt thereof, such as a fumaryl halide (e.g. fumaryl chloride), which contains unsaturated carbon-carbon double bonds that can be used for in situ crosslinking, is copolymerized with poly(caprolactone) diol in the presence of an alkali metal salt. The resulting photocrosslinkable biocompatible and bioresorbable poly(caprolactone fumarate) biomaterial is useful in the fabrication of injectable an in-situ hardening scaffolds for application in skeletal reconstruction.