Lead based ceramics have different problems for device processing and human health. That is why; these are not considered as suitable materials to be used for various technological applications. Human health has serious threat against toxicity of lead and if inhale, it replaces the calcium bonding sites within the human body that disturbs the nerves pulse transmission, heart activity and blood clotting, which needs calcium as a necessary element. Furthermore, once absorbed, it is very difficult to remove it from human organisms. Such severe issue compelled material scientist to develop human friendly lead-free piezoelectric ceramics with emerging properties. Lead-free piezoelectric ceramics [(Ba0.85Ca0.15)(Ti0.90Zr0.10)O3-xBiErO3 (BCTZ-xBE)] doped with a new doping material BiErO3 (BE) has been synthesized successfully via solid state reaction technique, and their structural, dielectric, ferroelectric, and piezoelectric properties have been investigated. A high dielectric constant with very low dielectric loss and high remnant polarization followed by a low coercive field has been obtained with the addition of x = 0.5 BE. Bulk ferroelectric hysteresis loops were obtained with a maximum polarization P max = 26.7 μC/cm2 and a saturation polarization Ps = 16.65 μC/cm2 along with a coercive field of E c ≈ 2.45 kV/cm. Results demonstrate an induced-strain increasing from ~ 0.11 to ~ 0.24 for x = 0.5, excellent piezoelectricity with d33 = 560 pC/N, kp = 56%, Qm = 196, εm =11200, and tanδ = 0.01. The Effect of BiErO3 (BE) as a doping material on the structural, dielectric and ferroelectric properties of (KNa)NbO3 (KNN) ceramics was explored in this research. Coexistence of two phase regions was confirmed through Le-Bail and Rietveld refinement in the composition range at x = 0.5% and x = 1.0%. The addition of BE content led to a decrease of the grain size and the ceramics became denser. Bulk P-E hysteresis loops were obtained with a maximum polarization of Pmax = 30.56 μC/cm2 and a remnant polarization of Pr = 25.10 μC/cm2, along with a coercive field of Ec ~ 11.26 kV/cm. The results revealed that a field strain value of ~ 0.26 for x = 0.5% of BE substitution was attained. This presents outstanding piezoelectric and dielectric properties. The lead-free piezoelectric, Bi0.5Na0.5TiO3, was synthesized with varying amounts of Manganese (Mn) doping (x = 0.00, 0.02, 0.05, 0.10, 0.15) on the B-site to replace Ti4+ cations. Herein, the doping limit of Mn is explored along with its effects on the structure and properties of these materials. The temperature-dependent dielectric properties of the materials with a higher manganese doping level have also been comprehensively investigated in the temperature range of 10–700 K. All samples show a high dielectric permittivity, εr ~ 4979–3626 at Tm ~ 550–600 K, along with a low dielectric loss. The site occupation and valence fluctuation of Mn2+/3+/4+ and Ti3+/4+ were characterized by X-ray Photoelectron Spectroscopy (XPS) and Electron Spin Resonance (ESR) for the BNTM-10 ceramics. The magnetic study shows that doping with Mn leads to a complex magnetic state, where there is possible clustering of Mn ions, with inter- or intra-cluster interactions becoming dominant at approximately 50 K. The results revealed a paramagnetic behaviour for the Mn-doped BNT at higher doping levels. This paramagnetism can be ascribed to the exchange of the coupling interaction between Mn3+/2+ ions and Ti4+ vacancy. These samples may be considered as alternative to lead-free materials with magneto-electric coupling.