The material properties of the polymers obtained via FROMP were characterized by DSC and dynamic mechanical analysis (DMA), and the results are summarized in Figure . The polymers obtained by ROMP of 5a were characterized only by DSC analysis. FROMP of monomers 3b and 3c produced elastomeric polymers with low glass transition temperature (Tg) (Figure ). DMA results (Figure ) revealed temporary rubbery plateaus, constant storage modulus above the Tg, likely originating from polymer chain entanglement. Substitution of a methyl substituent with chlorine marginally increased the Tg from -3 °C to 9 °C. Introduction of a methyl substituent on the furan moiety increased the Tg of materials significantly; with the same substituents on the benzyne moiety, the Tg changed from -3 °C (3b) to 135 °C (4b). We posit that the methyl group on the furan moiety hinders the rotation of the repeating units, leading to less flexibility requiring more energy needed for long range segmental motion of the polymer chains and consequently, higher Tg. This hypothesis is also supported by DSC tests showing higher Tg for poly-5a (ROMP, 162 °C) compared to poly-4a (FROMP, 133 °C; ROMP, 137 °C).