Multiferroic solid solution of (Ba0.85Ca0.15) (Zr0.1Ti0.9)O3, and BiFeO3, with stoichiometry 1−x(0.98BCZT-0.02BFO)xCuO; (0.0 ≤ x ≤ 4.0 wt %) were prepared via mixed oxide solid-state reaction (MOSSR) route sintered at 1075 °C. All samples were analyzed by X-ray diffraction, Fourier transform infrared spectrometer, field emission scanning electron microscopy, and impedance spectroscopy, respectively. XRD results confirmed the formation of a stable solid solution in pure composition with tetragonal symmetry, while the addition of CuO shows tetragonal to pseudocubic transformation. Absorption peaks in FT-IR spectra confirmed the presence of phases. SEM study revealed that dopant addition improved densification with the evolution of coarse grains. High-temperature impedance studies suggested that both grain and grain boundaries contribute to the impedance, while the addition of CuO promotes change defects at grain boundaries. Moreover, negative thermal coefficient resistance (NTCR) behavior with thermally activated dielectric relaxation is observed which makes these compositions suitable for thermal sensor applications. [ABSTRACT FROM AUTHOR]