Structural, electrical, and up-conversion (UC) properties of Na0.5Bi4.5-xErxTi4O15 (NBT-xEr(3+)) (0.00 < x < 0.40) ceramics have been studied. All the ceramic samples possessed a single-phase orthorhombic structure. The unit cell volume, the lattice parameters a, b, and c, and orthorhombic distortion analyzed on the basis of Rietveld refinement were observed to decrease with increasing Er3+ contents (x). The average values of grain size were found to slightly decrease with increasing x. Raman spectroscopy revealed that (Bi2O2)(2+) layers remained unaffected in the modified compositions, and Er3+ substitution for Bi3+ occurred predominantly at the A-site in the perovskite blocks causing the cationic disorder and a slight decrease in the TiO6 octahedral distortion. NBT-xEr(3+) ceramic with x = 0.20 achieved the optimized photoluminescence. The relative intensity of green and red UC emissions could be tuned by changing Er3+ ions concentrations. Ferroelectric measurements revealed that Er3+ doping led to reduction in 2P(r) and 2E(c). However, dielectric measurements showed that the incorporation of Er3+ ions increased T-c with simultaneously lowered tan at high temperature, implying that this ceramics can be suitable for high-temperature sensor applications.