Metathesis step-growth polymns. in ionic liqs. (ILs) was explored to take advantage of the high b.ps. of ILs, thereby permitting the use of low pressures at high temps. Optimization reactions found that high polymers form efficiently using small amts. of catalyst and short reaction times. For example, high mol. wt. main-chain triptycene polymers with high triptycene incorporation were synthesized. This new methodol. is applicable to various metathesis reactions that require removal of volatile byproducts as a driving force, including acyclic diene metathesis (ADMET). [on SciFinder(R)]