<p>In the present study, a series of bismuth-doped barium titanate (Ba_1 − xBi_xTiO₃, 0 ≤ x ≤ 0.15) ceramics were synthesized via the sol-gel method to explore a sustainable alternative to the conventional high-temperature solid-state technique. In comparison to the solid-state process, the sol-gel method adopted lower synthesis temperatures that minimized bismuth volatilization and resulted in a controlled crystallite growth and defect engineering at the nanoscale. An extensive structural, microstructural, optical, and electrical analyses revealed that the composition x = 0.05 achieved a favourable combination of properties, that included enhanced dielectric response, improved polarization behaviour, and a reduced optical band gap. As compared to the other synthesized compositions, x = 0.05 also exhibited the largest grain size, stable tetragonality, and a lower Curie temperature. Higher Bi concentrations showed either a suppressed dielectric performance or increased hysteresis losses, thus, highlighting the impact of compositional sensitivity of Bi-doped BaTiO₃ ceramics prepared through sol-gel chemistry. The main novelty of this study lies in demonstrating that controlled low-concentration Bi doping facilitated by the sol-gel technique creates an optimal balance of lattice distortion, oxygen vacancy formation, and electronic structure modification which collectively impact the material’s optical, dielectric, and ferroelectric properties. Thus, the “low-dopant optimum” for the Ba_1 − xBi_xTiO₃ ceramics serves as an effective strategy for achieving improved energy storage and electro-optic characteristics.</p>