<p>Barium titanate (BaTiO₃) is a cornerstone lead-free multifunctional ceramic; however, its application in high-performance sensors is often limited by its inherent electrical properties. In this study, we utilize a co-doping strategy involving Ca²⁺ at the A-site and Sn⁴⁺ at the B-site to engineer the phase structure and optimize the electrical properties of BaTiO₃ ceramics. A systematic investigation into the crystal structure, morphology, and electrical properties on barium titanate–calcium stannate (BaTiO₃–CaSnO₃) reveals that Ba_0.9Ca_0.1Ti_0.9Sn_0.1O₃ ceramics achieve a superior balance of properties, including a high piezoelectric coefficient (<i>d</i>₃₃ = 570 pC/N), a planar electromechanical coupling factor (<i>k</i>_p = 0.47), and a mechanical quality factor (<i>Q</i>_m = 361). Additionally, the material exhibits an excellent pyroelectric coefficient (<i>p</i> = 9.37 × 10^–4 C/m²/K) and favorable figures of merit (<i>F</i>_<i>i</i> = 4.54 × 10^–10&#xa0;m/V, <i>F</i>_<i>v</i> = 8.15 × 10^–3 m²/C, and <i>F</i>_<i>d</i> = 1.58 × 10^–5&#xa0;Pa^–1/2). These results demonstrate that phase-boundary-tuned BaTiO₃–CaSnO₃ ceramics are highly competitive candidates for sustainable, high-sensitivity piezoelectric and pyroelectric device applications.</p> Graphical abstract <p></p>