An efficient and practical method has been developed for the divergent synthesis of N-arylenaminones and 3-aroylquinolines from 2-aminoaryl ketones and N,N-dimethylenaminones in the presence of 4-toluenesulfonic acid through synergistic control of the temperature and amount of catalyst. Furthermore, gram-scale synthesis and synthetic applications have been evaluated. Features of this protocol include controllable results, mild conditions, good functional-group tolerance, operational simplicity, and excellent yields.