The unique coupling between B and N atoms as a result of co-doping could result in novel electronic structures in graphene. In this work, role of synergistic coupling effect of boron and nitrogen while codoping by systematically varying the concentrations of boron and nitrogen precursors is used to analyse the effects on electrochemical sensing of dopamine and hydrogen peroxide and supercapacitance performance. When compared with single doped samples (B and N), the codoped samples exhibited better supercapacitance and electrochemical sensing. Different boron and nitrogen doped graphene (BNGn (n = 1-5)) samples have been synthesized to modulate the electronic structure and surface states in order to improve the electrochemical performances. BNG5 sample shows a high specific capacitance of 378.7 F/g at 0.145 A/g in 1.0 M H2SO4, a threefold increase over single-doped graphene due to the high boron content that resulted in the highest B–N content. These samples show 92.11% cycling retention after 2000 cycles. Thus, B,N codoped samples can be tailored to be promising supercapacitor electrode materials. Excellent nonenzymatic dopamine and hydrogen peroxide sensing performance shown by BNG2 sample with 0.15 μM and 0.018 μM limit of detection (LOD) in 0–120 μM and 1–12 mM range respectively, was due to the high content of BC2O, BCO2, graphitic and oxidized N dopant species. Thus, this work brings to fore the different moieties which play crucial role in enhancing the supercapacitance (B–N, BC2O) and sensing behavior (oxidized dopants) for B,N codoped graphene. This opens up avenues to tailor doped graphene for specific applications.