Piezoelectric ceramics such as PbZr1-xTixO3 (PZT) show enhanced electro-mechanical properties at morphotropic phase boundary (MPB) separating two ferroelectric polar phases in the compositional phase diagram. Designing MPB in Pb-free perovskite oxide is challenging due to the lack of suitable polar tetragonal oxide with high Curie temperature. In this study, we explored the BiFeO3 – Bi0.5K0.5TiO3 – BaTiO3 ternary phase diagram and searched for Bi-rich perovskite oxides as candidates for piezoceramics near MPB. The phase diagram offers a Bi-rich polar tetragonal (T[001]) phase [0.75BaTiO3–0.25(K0.5Bi0.5)TiO3] and a well-known rhombohedral (R[111]) phase BiFeO3. A solid solution is observed in the entire range between the T[001] phase and the R[111] phase. Structural investigation through powder diffraction and Raman spectroscopy studies suggests the existence of a complex region (MPB), well separated by the rhombohedral and tetragonal phases. The composition (Bi0.670K0.050Ba0.280)(Fe0.62Ti0.38)O3 at the MPB shows a large signal piezoelectric coefficient of d33* = 41.5 pm/V at room temperature.