ABSTRACT: The comprehensive investigation of dielectric and impedance properties of (0.67 − x)BiFeO3-0.33BaTiO3-xKNbO3 relaxor ferroelectrics has provided insights into the impact of composition, temperature, and frequency on the dynamics and relaxation processes of polar nanoregions (PNRs). The presence and distribution of defects, introduced by the substitution of KN for BF, has a significant impact on PNRs.