Both single phase lead-free cubic pyrochlore bismuth zinc niobate (BZN)-based dielectric materials with a chemical composition of Bi.sub.1.5Zn.sub.(0.5+y)Nb.sub.(1.5−x)Ta.sub.(x)O.sub.(6.5+y), with 0≦x<0.23 and 0≦y<0.9 and films with these average compositions with Bi.sub.2O.sub.3 particles in an amorphous matrix and a process of manufacture thereof. The crystalline BZNT-based dielectric material has a relative permittivity of at least 120, a maximum applied electric field of at least 4.0 MV/cm at 10 kHz, a maximum energy storage at 25° C. and 10 kHz of at least 50 J/cm.sup.3 and a maximum energy storage at 200° C. and 10 kHz of at least 22 J/cm.sup.3. The process is a wet chemical process that produces thin films of Bi.sub.1.5Zn.sub.(0.5+y)Nb.sub.(1.5−x)Ta.sub.(x)O.sub.(6.5+y) without the use of 2-methoxyethanol and pyridine.