Polymeric ionic liquid poly(imidazolium chloride-1,3-diylbutane-1,4-diyl) with imidazolium cation groups built into the main chain was prepared using two different routes in 92-95% yield, and characterized by FT-IR, 1H, 13C NMR, TGA, and elemental analysis. The first method involved the heating of neat 1-(4-chlorobutyl)-1H-imidazole, whereas the second method involved the heating of an equimolar mixture of 1,1′-(1,4-butanediyl)-bis- imidazole and 1,4-dichlorobutane. © 2010 Springer-Verlag.