Physical properties, such as densities, rho, and refractive indices, n, for the binary mixtures of 1-methyl-3-octylimidazolium tetrafluoroborate [Omim][BF4] with ethylene glycol monomethyl ether (EGMME; C1E1), diethylene glycol monomethyl ether (DEGMME; C1E2), and triethylene glycol monomethyl ether (TEGMME; C1E3) have been measured over the whole composition range. Experimental densities were used to estimate excess molar volumes, V-m(E), apparent molar volumes, V-phi,V-i, partial molar volumes, (V) over bar (m,i), excess partial molar volumes, (V) over bar (E)(m,j), and their limiting values at infinite dilution, V-phi,i(infinity), (V) over bar (infinity)(m,i), and (V) over bar (E,infinity)(m,i), respectively. Volumetric results have been analyzed in the light of Prigogine-Flory-Patterson (PFP) statistical mechanical theory. Deviations in refractive indices Delta(phi)n have been calculated from experimental measurements of refractive indices, n. Excess properties are fitted to the Redlich-Kister polynomial equation to obtain the binary coefficients and the standard errors. The results are compared with those of binary mixtures of 1-methyl-3-octylimidazolium tetrafluoroborate containing alcohols reported in the literature or the binary mixtures of 1-butyl-3-methylimidazolium hexafluorophosphate [bmim][PF6] with an alkoxyethanol reported in an earlier communication. (c) 2007 Elsevier Ltd. All rights reserved.