Abstract: The antibiotic properties of a series of hydroquinones were examined in an effort to study the quantitative structure activity relationship with the application of Topliss, Hansch and Free-Wilson methods.It seems likely that the pharmacological activity of the substituted hydroquinones. is realized by the charge transfer complex which is formed by the transfer of electrons from receptor site to the specific hydroquinone. In Hansch analysis, the parameter LEMO was calculated by molecular orbital technique and a better correlation was found in combination with othet parameters.The experimental values of lg(1/C) agree fairly with the values calculated by both Hansch and Free-Wilson equations.