To investigate if the polymer chain length could be further extended, the monomer to initiator ratio (M/I) was increased to 80 ºC or 160 ºC (Table , entries 1 and 2). At a cyclopropene loading of 160 the average molecular weight increased to 6.9 KDa while the Đ was 1.4. However, the relatively low yield, along with the [a] See ESI for experimental details. Yields reflect isolated and purified polymer.