Abstract Assuming a scenario of small-scale domain switching, the dimensions and configuration of the domain switching region preceding a clearly defined primarily monoclinic piezoelectric bi-material notch are determined by embracing the energetic switching principle and micromechanical domain switching framework proposed by Hwang et al. (Acta Metall Mater 43(5):2073€“2084, 1995. https://doi.org/10.1016/0956-7151(94)00379-V ) for a given set of materials, structure, and polarization alignment. The piezoelectric bi-material under consideration comprises piezoelectric ceramics PZT-5H and BaTiO 3 . The analysis of the asymptotic in-plane field around a bi-material sharp notch is conducted utilizing the extended Lekhnitskii€“Eshelby€“Stroh formalism (Ting in Anisotropic elasticity, Oxford University Press. 1996. https://doi.org/10.1093/oso/9780195074475.001.0001 ). Subsequently, the boundary value problem with the prescribed spontaneous strain and polarization within the switching domain is solved and their influence on the in-plane intensity of singularity at the tip of interface crack is computed. The effects of the initial poling direction on the resulting variation of the energy release rates are discussed.