Abstract
The recent developments in organoborane initiated Cl polymerization (chain grows by one atom at a time) of ylides opens unique horizons towards well-defined/perfectly linear polymethylenes (equivalent to polyethylenes, PE). On the other hand, atom transfer radical polymerization (ATRP) is an excellent and powerful controlled/living polymerization for polar monomers such as (meth)acrylates and styrenes. In this Chapter the partnership of these two living polymerizations towards the synthesis of well-defined PE (perfectly linear)-based block copolymers, with unprecedented macromolecular architectures, is presented. Some ideas about new ylide monomers are also discussed.