Densities and viscosities of binary ionic liquids mixtures, 1-(2-hydroxyethyl)-3-methylimidazolium tetrafluoroborate ([eOHmim][BF4]) + 1-butyl-3-methylimidazolium tetrafluoroborate ([bmim][BF4]), 1-(2-hydroxyethyl)-3-methylimidazolium tetrafluoroborate ([eOHmim][BF4]) + N-butylpyridinium tetrafluoroborate ([bpy][BF4]) and 1-butyl-3-methylimidazolium tetrafluoroborate ([bmim][BF4]) + N-butylpyridinium tetrafluoroborate ([bpy][BF4]) were measured over the entire mole fraction from T = (298.15 to 343.15) K. The excess molar volumes were calculated and correlated by Redlich-Kiser polynomial expansions. The viscosities for pure ionic liquids were analyzed by means of the Vogel-Tammann-Fulcher equation and ideal mixing rules were applied for the ILs mixtures. (C) 2014 Elsevier Ltd. All rights reserved.