With the solution-ROMP reactivities in mind, we next examined the FROMP activity of our monomers. After thermally initiating FROMP via a soldering iron, polymerization fronts were observed for 4a (monomer:G2 = 5000:1) (Figure , Supplementary Video S3). Monomers 3b and 3c, which displayed higher ROMP reactivity, exhibited faster front speeds than 4a even with TBP (Figure ). However, 3b and 3c did have reduced front temperatures compared with 4a, which might be a result of monomer consumption during resin preparation . Moreover, the front speed and max front temperature of 4b were slightly lower than 4a, possibly due to a lower concentration of reactive olefin moiety per volume in the resin. A similar trend was noted for 4b and 4c, with a stable front in 4c requiring a higher G2 concentration in the resin.