Present research accounts for the production of columbite type MgNb2O6 nanoparticles (MNO NPs) by solution combustion method, its application in photocatalytic degradation and electrochemical sensor studies. The resultant nanoparticles were well characterized by Powder X-ray diffraction (PXRD), Scanning electron microscopy (SEM), Transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FT-IR) and UV–Visible (UV–Vis) spectral studies. PXRD patterns showed that nanoparticles have orthorhombic phase with average crystallite size of ∼29 nm.The energy band gap of the sample was found to be 4.4 eV by Diffused reflectance spectroscopy (DRS) analysis. The MNO photocatalyst matrix influences excellent photocatalytic decolourization of Acid Red-88 (AR-88) and Fast orange red (FOR) dyes under UV light irradiation. The experiment show 86 % and 74 % dye decolourization respectively after 120 min irradiation. The holes (h+) are mainly responsible for excellent photocatalytic activities as confirmed by scavenger test. Electrochemical analysis was carried out to find the reversibility of the electrode reaction of electrode using 0.1 M KCl by Cyclic voltammetry (CV) and Electrochemical impedance spectroscopy (EIS) analysis. Thus, the prepared sample plays an excellent role in photocatalysis, electrochemical activity and chemical sensing applications.