From density and viscosity measurements excess volumes,VE, excess viscosities,nE, and excess free energies of activation for viscous flow,G*E, have been determined at 298.15 and 313.15 K for the binary mixtures of a halogenated (Cl, Br) benzene or cyclohexane with 2-butanol. The results show the influence of both the type of cyclic system and the halogen atom over the self-association of the 2-butanol.VEpresents predominant positive values, only showing negative ones with aromatic derivatives at 298.15 K in a small zone. FornEandG*E, all mixtures present negative values over the whole composition range at two temperatures.