!!Reactive Organoboron Polymers We explored the synthesis of novel polymers having a boron atom in the main chain by hydroboration polymerization. Their reaction with various nucleophiles via chain transformation provided a large number of functionalized polymers. {{ref_image image_4.gif}} Fig. 1 !!¦Ð-Conjugated Organoboron Polymers One of the most interesting applications of organoboron polymers is incorporation of a boron atom into -conjugated systems, because a boron atom has a vacant p-orbital. Recently, we succeeded in the synthesis of novel ¦Ð-conjugated organoboron polymers by hydroboration polymerization of arylborane with aromatic diyne. The extention of ¦Ð-delocalization through the vacant p-orbital of a boron atom was shown. {{ref_image image_5.gif}} Fig. 2