The liquid-liquid equilibrium (LLE) data of four binary systems (o-dichlorobenzene(1) + 1,2-ethanediol (2)), (o-dichlorobenzene(1)+ 1,2-propanediol(2)), (nitrobenzene(1)+ 1,2-ethanediol(2)) and (nitrobenzene(1)+ 1,2-propanediol(2)) under atmospheric pressure and at temperatures 290-400 K were determined in this study. The results indicated the mutual solubility between all the binary systems increased with temperatures. The NRTL and UNIQUAC models were applied to correlate the liquid-liquid equilibrium data. In addition, the data were correlated well by the UNIFAC (Do) group contribution method, in which 1,2-ethanediol was treated as a single DOH group (methodl) or two -CH2OH groups (method II), and 1,2-propanediol was divided into groups (-CH3, -CH2OH, -CHOH). The new group interaction parameters for (ACC1-DOH, ACNO(2)-DOH, ACCI-CH2OH, ACNO(2)-CH2OH, ACH-CH2OH) were obtained by the experimental LLE data regression. Moreover, all the new interaction parameters except the group ACNO2-DOH were proved reliable, among which the parameters for ACC1-DOH were proved by estimating the binary system (chlorobenzene + 1,2-ethanediol) LLE data from literature and the parameters for (ACCI-CH2OH, ACNO2-CH2OH, ACH-CH2OH) were proved by estimating the LLE data of the (o-dichlorobenzene(1)+ 1,2-ethanediol(2)) and (nitrobenzene(1) + 1,2-ethanediol(2)) binary systems in this work. (C) 2014 Elsevier B.V. All rights reserved.