New routes have been developed for the synthesis of blue-emitting conjugated polymers designed to show stable blue-emission inLEDs. Fluorenes bearing polyphenylene dendrimer side-chains have been made by a new route in which the dendrimer substituentsare built up on a biphenyl which is then ring-closed to give the uorene. This route can be used to make uorenes with a range offunctionalised rst and second generation dendrimer substituents, as monomers for new blue-emitting polymers. Polyindenouo-renes bearing aryl substituents have been made and found to display much stabler blue-emission than previous polyindenouorenes.