Perovskite-phase developments in partially/fully substituted (Ba,Pb)(Zn1/3Nb2/3)O-3, synthesized via B-site precursor routes, were investigated. The pyrochlore structure, present at no barium content, was immediately replaced by perovskite with a small amount (greater than or equal to 8 at.%) of barium substitution. Variations in the lattice parameters of the pyrochlore and perovskite structures were studied. The weak-field radio-frequency dielectric constants and losses of the system ceramics were examined. A highest maximum dielectric constant of 9000 (76 degrees C, 1 MHz) was observed at 8 at.% barium substitution. The dielectric-constant spectra were analyzed further in terms of diffuseness characteristics (e.g., diffuseness exponent and degree of diffuseness). The dielectric hysteresis leaps of the ceramics were measured. The microstructures of the sintered ceramics also were observed.