Nucleophilic substitution reactionsof 1 -(Y-pheny1)ethyl chlorides with X-anilines have been investigated in methanol at 65.0"C. A n isokinetic point is obtained at a,?= ca. -0.23 with px = 0; the sign of px changes at this point from positive for the relatively strong electron donating Y substituents t o negative for the more electron withdrawing Y substituents.The magnitude of the cross-interaction constant, pxy, between the substituents X and Y is unusually large with the relatively small magnitude of pxo resulting in an observable isokinetic point at PXU a,+= -~ = -023.