As epoxy curing agents three alkenyl succinic anhydrides (ASA) with varying side chain length (2-octenyl, 2-dodecenyl and 2-hexadecenyl succinic anhydride) were prepared by the ene synthesis and thermal and mechanical properties of a bisphenol A epoxy resin cured with the ASA's were measured. With increase in the side chain length of the ASA the Tg, the tensile strength and the impact strength decreased. All the cured samples exhibited excellent transparency and flexibility.