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New layer-structured ferroelectric polycrystallines, Na 0.5 Nd x Bi 4.5-x Ti 4 O 15 (x = 0-2.5; NNBTO-x), were prepared, and the tailoring effects of neodymium (Nd) were investigated thoroughly. A relaxation in orthorhombic distortion was caused by the Nb substitution, and the compositions with high x value modification tended to crystallize in tetragonal. Rietveld structure refinements revealed that NNBTO-0.5 and NNBTO-1.5 crystallized in orthorhombic space group A2 1 am at room temperature, and Nd/Bi combinations occupied the cation sites of the (Bi 2 O 2 ) 2+ layers. The Nd substitution had strong impacts on electrical properties of the NNBTO-x. Ferroelectric to paraelectric phase transition temperature (T c ) was lowered from about 670 °C to one temperature below 200 °C. Ferroelectric (remnant) polarization (P r ), piezoelectric activity (d 33 ) and field-induced strain (S 33 ) first increased, and then decreased drastically owing to a significant degradation in spontaneous polarization (P s ). In addition, high temperature resistances of the NNBTO-x were discussed and the conduction mechanisms of them were explored. The NNBTO-0.5 with a T c of 670 °C had a P r of 10.8 µC/cm, a d 33 of 24.5 pC/N and a S 33 of about 0.04%, due to the decrease in oxygen vacancy concentration and the local lattice distortion.