Abstract: The invention relates to a curable thiol-ene composition comprising either compound A and compound B, or a compound B further comprising polythiol functionality as defined under (A), wherein (A) a polythiol, (B) a compound having a plurality of cyclic ene groups thereon, wherein said compound (B) comprises a carbonyl group directly attached to at least one cyclic ene group and comprises at least one hydrogen donating group, wherein the distance between at least one of said cyclic ene groups and at least one of said hydrogen donating groups is at least two skeletal bonds, wherein compound (B) does not contain a (meth)acrylate group, and 0-10 wt. % of a (free-radical) photoinitiator. The invention further relates to the use of such composition fiber optical coating, stereolithography resin, medical coating and adhesive.