The ring-opening metathesis polymerization (ROMP) of 1,3,5,7-cyclooctatetraene (COT) in the presence of a chain transfer agent (CTA) with a highly active ruthenium olefin metathesis catalyst resulted in the formation of soluble polyenes. Small molecule CTAs containing an internal olefin and a variety of functional groups resulted in soluble telechelic polyenes with up to 20 double bonds. Use of polymeric CTAs with an olefin terminus resulted in polyacetylene block copolymers. These materials were subjected to a variety of solution and solid phase characterization techniques including H-1 NMR, UV/vis, and FT-IR spectroscopies, as well as MALDI-TOF MS and AFM.