A new dielectric binary mixture formula that generalizes Beer＇s equation is derived by imposing an effective medium theory on the simple rule of mixtures modified by the addition of an interaction term. Dielectric constants of the binary system carbon tetrachloride/1,2-dichloroethane measured at different frequencies and of carbon tetrachloride/butan-2-ol at different temperatures are used to test the applicability of the new mixture formula. Goodness of fit to the experimental data is found.