Presented here is the use of metastable-state photoacid (mPAH) in solid-state under visible light illumination to generate reversible solar photovoltaics. To achieve this, a solid-state cell was designed, in which mPAHs were functionalized with thiol moiety for covalent linkage to a gold surface. Through the absorption of visible light at 470 nm, mPAH releases protons, which are transported through solid electrolytes, thereby generating a photovoltage of 200 mV. The voltage is approximately 30 times greater than the solid-state cell without mPAH. On the other hand, when visible light is absent, mPAH uptake the protons and cease photovoltage. This fabricated solid-state cell shows good reversibility, reproducible photovoltage changes and potentially opening up new insights for lower power electronics applications.