Adsorption of organic molecules can be a better choice than traditional chemical doping to achieve effective doping of 2D materials. The adsorption of organic molecules on square/octagon-phase (S/O-phase) arsenene is investigated and promoted the possibility of developing p–n junctions. In particular, it is found that adsorption of F4-TCNQ or TCNE molecules leads to effective p-doping. Adsorption of DMPD or TTF molecules leads to less effective n-doping. Interestingly, in the case of TTF adsorption strain engineering can be used to greatly improve the material properties. Therefore, both effective n- and p-doping of S/O-phase arsenene can be realized.