Solid solutions on the base of composition from morphotropic phase boundary (1–x) BiScO ₃–x PbTiO ₃ with x = 0.64, 0.645, 0.65 were prepared from nitrates solutions. Variations in phase content, structure parameters, microstructure, dielectric and piezoelectric properties of dense ceramic samples were studied. The first-order phase transitions were observed at temperatures near 700 K. The influence of the processing conditions on the morphology, temperature of phase transitions, and dielectric parameters was observed. In some ceramics effect of dielectric relaxation was observed at high temperatures. This effect was explained by the contribution from ionic transport due to the oxygen vacancies creation during high temperature sintering.