Ceramics in the (1 - x)PbZrO3-x[0.3Bi(Zn1/2Ti1/2)O-3-0.7PbTiO(3)] solid solution system with 0.48 <= x <= 0.56 were investigated. A morphotropic phase boundary separating rhombohedral and tetragonal perovskite phases was identified at x = 0.52. This composition displays the maximum remanent polarization P-r of 40.7 mu C/cm(2) and the best piezoelectric coefficient d(33) of 311 pC/N in the pseudo-binary system. However, the Curie temperature T-c for this MPB composition is 291 degrees C, much lower than initially expected.