The threat of chem. warfare agents (CWAs) necessitates the development of functional materials that not only quickly detect the presence of CWAs but also actively protect against their toxicity. The authors have synthesized responsive units that exhibit colorimetric responses upon exposure to CWAs and incorporated them into a versatile detection platform based on copolymers prepd. by ring-opening metathesis polymn. (ROMP). The theor. detection limits for CWA simulants in soln. for these polymers are as low as 1 ppm. By incorporating hydrogel-promoting units as pendant chains, the authors are able to obtain polymers that instantly respond to CWA vapors and are easy to regenerate to the deactivated state by simple treatment with ammonium hydroxide vapor. The authors further demonstrate a collapse of the polymer gels in response to trifluoroacetic acid (TFA), a strong acid that produces a more fully ionized state as a result of its more caustic nature.