Nine 1-allyl-3-alkylimidazolium ([ACnIm]) or 1-vinyl-3-alkylimidazolium ([VCnIm]) dicyanamides (DCA) were prepared and characterized, and their physicochemical properties were studied in detail. Except for [AVIm]DCA and [AC4Im]DCA, the other dicyanamides with hexyl or longer alkyl chains on the cation exhibited the characteristic of hydrophobicity. Among them, [AC8Im]DCA and [AC10Im] DCA were found to possess similar densities to water, i.e. 1.007 g cm
3 and 0.988 g cm
3 at 25 C, respectively. Interestingly, a reversible phase reversion of a [AC8Im]DCA/H2O mixture was observed as the temperature varied. These environmentally-friendly liquid materials have potential applications as precursors for syntheses of conducting polymeric materials.

★★★☆☆ J. Mater. Chem., 2011, 21, 6864–6868