<p>This work presents a comprehensive investigation of the structural, magnetic, optical, and dielectric properties of praseodymium-doped barium hexaferrite nanomaterials, BaPr_<i>x</i>Fe_{12−<i>x</i>}O₁₉ (<i>x</i> = 0.00 and 1), synthesized via a heat treatment method at 850&#xa0;°C. Fourier transform infrared (FTIR) spectroscopy confirms the formation of the hexaferrite phase through characteristic metal–oxygen vibrational modes and enables the evaluation of force constants, bond lengths, and functional groups. X-ray diffraction (XRD) analysis reveals the formation of M-type hexaferrite with a hexagonal structure, accompanied by a minor BaFe₂O₄ secondary phase, while providing detailed crystallographic parameters influenced by Pr³⁺ substitution. Thermogravimetric analysis (TGA) demonstrates excellent thermal stability of the samples beyond 780&#xa0;°C, indicating their suitability for high-temperature applications. Magnetic characterization using vibrating sample magnetometry (VSM) shows a notable enhancement in magnetic behavior with Pr incorporation, attributed to lattice distortion and modified superexchange interactions. Optical properties investigated via UV–Visible spectroscopy reveal a direct band gap, which increases systematically with Pr concentration, highlighting effective band gap tuning—one of the key novel outcomes of this study. Dielectric and ferroelectric measurements indicate that Pr³⁺ ion substitution suppresses electrical leakage by stabilizing the lattice and hindering charge carrier mobility, thereby enhancing remnant polarization and coercive polarization. Overall, the improved structural stability, enhanced magnetic performance, tunable optical band gap, and favorable dielectric characteristics establish Pr-doped BaFe₁₂O₁₉ nanomaterials as promising multifunctional candidates for advanced optical, magnetic, electronic, and potential biomedical applications.</p>