A novel sulfated β-cyclodextrin/PVP/MnCO₃ composite has been synthesized for a parallel-connected supercapacitor and dye-sensitized solar cell (counter electrode). β-Cyclodextrin has sulfonated, thermally cross-linked with PVP, and incorporated with MnCO₃ nanoparticles. The composite electrode exhibited 202.6 F g⁻¹ capacitance, 197.96 W h kg⁻¹ energy density, 5.57% η (DSSC) and 70% performance up to 200 °C with a [BMI][TFSI] electrolyte.