In this paper, the authors have report the fabrication of MnS2 with reduced graphene oxide (MnS2-RGO) composite through co-precipitation route. The prepared samples were characterized by analytical instruments like XPS, FTIR, XRD, BET, SEM-EDX, TEM, UV-DRS and TGA for understanding the optical, electrochemical, structural and thermal properties. The prepared composites and bare MnS2 were examined for their photocatalytic performance by the degradation of o-nitrophenols under visible light irradiations. However, MnS2-RGO-2 composite was the most effective photocatalyst for the degradation of o-nitrophenols in 75 min and can be recycled for continuous five cycles. The MnS2-RGO composites and bare MnS2 were further examined their antimicrobial activity over E.coli, S.aureus, S.typhi and V.cholera. In addition, the effect of RGO on enhanced catalytic degradation of o-nitrophenols under visible light irradiations and antibacterial activity as prepared composite exhibits tremendous properties of both MnS2 and RGO.