Intermolecular interaction of polar-nonpolar binary systems such as aminebenzene, alcohol-cyclohexane, and acetic acid-dioxane, and of polar-polar binary such as amine-water, alcohol-water, and acetic acid-water were studied by a viscosity method. These results exhibit the existence of the maximum viscosity in all polar-water binary systems, suggesting interesting intermolecular interactions. The maximal viscosity and their positions are 2.19, 2.44, and 2.94 centi poise (cP), and 80,50, and 65vol.%, for acetic acid-water, n-propyl amine-water, n-propyl alcohol-water binary systems respectively, in which amine or alcohol molecule is bound by about three molecules of water and two molecules of acetic acid, a dimer, interact with two water molecules. The dimer of acetic acid makes the intermolecular frictions in dioxane increase but them in cyclohexane or benzene decrease. No evidence for a dimer of alcohol or amine are detected by this viscosity method.