A copper-catalyzed highly para-selective electrophilic aromatic alkylation of monosubstituted simple arenes has been accomplished. This method provides a practical platform for the transformation from simple commercial arenes to well-defined di- and multisubstituted aromatics with high added value. Control experiments and DFT calculations reveal that the achievement of the excellent site-selectivity is ascribed to the controlled deprotonation of the Wheland intermediates. Remarkably, the type of alkylating regent has been shown to have a significant impact on site-selectivity.