Realizing the fact that there can be more degrees of freedom for physical and chemical properties, very recently, a new ternary pentagonal prototype, composed of B, N, and C atoms, pentagonal boron nitrogen carbide (p-BCN), has been theoretically predicted, which is mechanically, thermally, and dynamically stable direct bandgap semiconductor with excellent piezoelectric response . These three abundant neighboring elements in the periodic table have an almost equivalent atomic size and mass, and lightweight are benign to the environment to form p-BCN exhibiting intrinsic polarization and piezoelectricity , and lattice thermal conductivity up to 97.49 Wm -1 K -1 at room temperature . Moreover, the hydrogenation in pristine p-BCN changes it from a direct bandgap of 1.70 eV to an indirect bandgap of 4.46 eV. The bandgap of hydrogenated p-BCN is tuneable up to 3.26 eV under the biaxial strain. Although the elastic modulus tensor is reduced due to the hydrogenation, the spontaneous polarization is reported to be significantly enhanced .