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In this study, Sm 3+ doped Na 0.5 La 0.5 Bi 8- x Sm x Ti 7 O 27 (NBT-BITL- x Sm, x = 0, 0.01, 0.015, 0.02, and 0.03) ceramics were synthesized via a conventional solid-state reaction process. The structural, electrical, and photoluminescence properties of NBT-BITL- x Sm ceramics were systematically investigated. The crystal structure of NBT-BITL- x Sm was refined using XRD Rietveld refinement and found to possess a single orthorhombic structure at room temperature. Raman spectroscopy revealed that Sm 3+ ions preferred to substitute for Bi 3+ located in the A-sites of pseudo-perovskite layers, inducing a slight decrease in orthorhombic distortion. Strong characteristic emission peaks of Sm 3+ ions were observed in orange-red regions under a 407 nm laser source, and the sample with x = 0.015 achieved the optimal photoluminescent property. Dielectric measurements showed double anomaly permittivity peaks at the temperature of 589 and 600 ∘ C ( T m and T c , respectively). The complex impedance spectrum indicated that the electrical conductivities mainly originated from crystal grains at high temperature. The activation energy was calculated to be 1.37–1.44 e V from Arrhenius fitting results. After Sm 3+ substitution, the activation energy for conductivity was increased as a result of reduced oxygen vacancies. [ABSTRACT FROM AUTHOR]