Herein, N2-selective β-thioalkylation of benzotriazoles with unactivated alkenes and styrenes is reported. The N2-selective β-thioalkylation of benzotriazoles is highly stereospecific and works under simple and mild conditions, exhibiting excellent functional group tolerance. The high N2-selectivity is a consequence of the combination of hydrogen bonding and Lewis acid/base activation, which reverses the N2-position to be favored for alkylation.