Overall, this study revealed that TCNs and TCNDs are a synthetically accessible class of ROMP monomers that do not compromise on activity or controlled polymerization behavior in comparison to other commonly used monomers (e.g. exo-NBs). In particular, TCND-(CO2Me)2 is a uniquely promising monomer due to its ease of synthesis (2 steps from commercial materials), fast ROMP kinetics, and its innate activity towards post-polymerization functionalization with thiols; we envision its future widespread use for functional polymer design.