The main objective of this study is to develop the reduced graphene oxide (rGO) with magnesium oxide (MgO) nanoparticles. The obtained nanocomposite was characterized by using XRD, SEM and EDAX techniques. The developed rGO/MgO nanocomposite was utilized for antioxidant property. The Antioxidant activity of rGO, MgO and rGO/MgO nanocomposite were estimated using DPPH assay shows a greater antioxidant activity 83 % and lower IC50 about 2609.23 mg/mL for rGO/MgO nanocomposite. The cyclic voltammetry (CV) analysis was performed using carbon paste electrode in 1M KOH electrolyte. From CV studies, electrochemical reversibility at scan rate 10 mV/s (ER= 2.0810−6), proton diffusion co-efficient (D= 1.765 × 10−4) and capacitance (𝐶𝑠𝑝 = 173𝐹𝑔−1) has been improved significantly. The photodegradation of malachite green was carried out for rGO, MgO and rGO/MgO nanocomposite shows a greater degradation about 93% and follows 1st order kinetics. Further, sensing property of the synthesized material by utilizing Ascorbic acid (BS-A), Resorcinol (BS-R) and Uric acid (BS-U) exhibit a good sensing in the oxidation region.