The condensation reaction between o-phenylene diamine and para-disuhstituted ben¬zils has been studied kinetically. The reaction has been followed spectrophotometrically, at constant temperature 20°C, in strong and weak acidic media. The reaction mûcture consists of 36 % water and 64 % methanol. The reaction was found to be second order in strong and weak acidic media. The rate-profile has been determined and the top of it was chosen as a common point for the study of the effect of different substiutents (e.g CH„ CHSO, Br, N02) on the reaction rate. The rate constants of the condensation reacti- ons between o-phenylene diamine and different disubstituted benzils have been obtained, the p value is estimated as + 2.11. The reaction mechanism has been found in accordance with the imine formation re¬action.