Abstract: Novel compounds have at least one perfluorocyclobutane ring and at least two functional groups suitable for forming condensation polymers. Preferably the compounds have a structures represented by Formula II: ##STR1## wherein R and R' independently represent optionally inertly substituted groups: X and X' represent any molecular structures which link R and R' with the perfluorocyclobutane ring; n and n' are the number of G and G' groups, respectively: and G and G' independently represent any reactive functional groups or any groups convertible into reactive functional groups. The compounds are preferably prepared by a process of thermally dimerizing trifluorovinyl compound to form a compounds of Formula IG.sub.n -R-X-CF.dbd.CF.sub.2wherein G represents G or G' in Formula II: X represents X or X' of Formula II: and n represents n or n' of Formula II, to form a compound having a perfluorocyclobutane group.