Halogenation is one of the most important ways to tailor the properties of graphene. We demonstrate for the first time that boron and nitrogen doping can effectively tune the interactions between halogen diatomic molecules and graphene from first principles calculations. Boron and nitrogen doping disrupt the regular pi-electron pattern and create spin density and orbital polarization. More interesting, nitrogen and boron doping not only significantly increases the binding energies of Cl₂, Br₂, and I₂ but also induces the spontaneous dissociation of F₂. The tunable effects from nitrogen and boron doping can adjust the interactions in a wide range. Overall, it is suggested that doping can be a very promising method for the facile halogenation of graphene.