In order to investigate the possible participation of propargyl group in Butler's cyclopolymerization process, a number of quaternary ammonium chlorides containing ally] and propargyl units are prepared in excellent yields. While the monomer containing two propargyl units as the only unsaturated groups did not undergo cyclopolymerization or cyclocopolymerization with sulfur dioxide, the monomer having one allyl and one propargyl groups afforded water-soluble homo- and co-polymers. The monomer diallylmethylpropargylammonium chloride gave cross-linked homopolymers, whereas its copolymer with sulfur dioxide was found to be linear and water-soluble. Careful analysis of the H-1 and C-13 NMR spectra revealed for the first time the participation of the propargyl units in Butler's cyclopolymerization process to yield polymers having five-membered cyclic structure embedded in the polymer chain. (C) 2004 Elsevier Ltd. All rights reserved.