We have developed a synthesis method of single-grain two-phase BaTiO3-(Mn0.5Zn0.5)Fe2O4 nanomaterials via a solid state reaction. The grains of BTO-rich samples were found to have a rod-like morphology with a high aspect ratio and a diameter of 200 nm, whereas the grains of MZF-rich samples had a tetrahedral/octahedral cross-section with a span of 200 nm. Such a synthesis of two-phase perovskite/spinel single-crystal grains with different grain geometries offers the potential to build new types of multiferroic materials.