<p>Europium-substituted lead-free 0.94Na_0.5Bi_0.5<i>-x</i>Eu_<i>x</i>TiO₃-0.06BaTiO₃ (<i>x</i> = 0 &amp; 0.25) nano ferroelectric ceramics were synthesized through a sol–gel processing route to investigate their multifunctional characteristics relevant to electrocaloric refrigeration, electrical energy storage, and photoluminescence applications. The partial replacement of Bi³⁺ by Eu³⁺ ions in the NBT–BT perovskite lattice alters the local structural symmetry and polarization mechanisms, particularly near the morphotropic phase boundary (MPB) where multiple ferroelectric phases coexist. Structural analyses confirm the successful incorporation of Eu³⁺ ions into the host framework, resulting in slight lattice distortion and improved phase stability, which subsequently influences ferroelectric domain configuration at the nanoscale. The electrocaloric response of the materials was evaluated by analysing the field-induced thermal variation associated with polarization entropy changes. The Eu-substituted composition (<i>x</i> = 0.25) exhibits a pronounced electrocaloric behaviour, producing a temperature variation (ΔT) of approximately 1.42&#xa0;K when subjected to an external electric field of 40&#xa0;kV/cm, indicating its potential applicability in solid-state cooling technologies. In addition to the electrocaloric response, the ceramics demonstrate promising electrical energy storage performance, characterized by enhanced recoverable energy density and improved charge–discharge efficiency while maintaining relatively low dielectric loss. The optimized composition achieves a recoverable energy density of about 1.32&#xa0;J/cm³ with an energy storage efficiency of nearly 80.13%. The simultaneous improvement in electrocaloric and energy storage properties highlights the role of Eu substitution in tuning the structural and polarization behaviour of NBT–BT nanoferroelectrics, suggesting their potential as environmentally friendly multifunctional materials for advanced energy storage and cooling applications.</p>