The reactivity of enes in the radical thiol addition follows the sequence NB > VE > alkene > AE > acrylate > maleimide > MA. This trend largely corresponds to decreasing electron density, with NB particularly reactive due to the release of ring strain and MA particularly unreactive due to intermediate radical stabilization. For our experiments we selected the NB and AE groups as enes with high and intermediate reactivity. In contrast to (meth)acrylate groups, NB and AE groups cannot undergo thiol-Michael addition which ensures that crosslinking proceeds only in the presence of radicals to give high temporal control over the network formation in photoinitiated systems. It also avoids side reactions with other nucleophiles e.g. on the cell surface leading to higher cell viability. In addition, NB and AE groups are not prone to autopolymerisation which should increase the polymers' storage stability.