The intrinsic auxeticity of materials has long been attributed to their unique geometric configurations. Triggering and enhancing auxeticity presents significant challenges, as many nanomaterials display subtle auxetic effects with a negative Poisson's ratio (NPR) typically above -0.4. This paper introduces three materials with identical symmetry—two-dimensional pentagonal structures Penta-B2×2Y2 (i.e., Penta-B2C4, Penta-B2N4, and JP-B2C2N2)—to investigate a novel mechanism influencing material auxeticity: electron transfer. Specifically, variations in electron transfer cause Penta-B2N4 and JP-B2C2N2 to show axial auxetic effects, whereas Penta-B2C4 demonstrates opposite behavior. The axial NPR of Penta-B2N4 is ∼ -0.05, while for JP-B2C2N2, it reaches ∼-0.46, significantly surpassing that of typical intrinsic auxetic materials. This represents an increase of approximately 920 % compared to Penta-B2N4. Additionally, JP-B2C2N2 features semi-metallic properties, where the conduction band minimum (CBM) and the valence band maximum (VBM) are tangent to the Fermi level. Consequently, minor alterations in external conditions can induce a transition between semiconductor and metallic states in JP-B2C2N2. Thus, the 2D material JP-B2C2N2 emerges as a promising candidate for nanoelectronic and electromechanical applications. Furthermore, this study also enhances the academic understanding of auxetic properties in nanomaterials by linking their mechanical and electronic characteristics and laying a theoretical foundation for further experimental exploration of auxeticity.