摘要： In recent years, the successful obtained of various boron nitride allotropes have raised exciting prospects of 2D material for nano device area. Herein, two novel two-dimensional boron nitride allotropes, a rectangular graphyne-like sheet (R-BNyne) and an O-functionalized R-BNyne nanosheet (R-BNOyne), are proposed and investigated by first principle calculations. The structural stabilities of metallic R-BNyne and indirect gap semiconducting R-BNOyne are proved through the phonon dispersion and Molecular Dynamic calculations. Furthermore, the adsorptions of CH4, CO, CO2, SO2 and H2 on R-BNyne and R-BNOyne have been calculated to explore the possibilities of being as gas sensors. The significant change of the current-voltage curve with and without SO2 adsorption on R-BNyne and R-BNOyne implies that both of them could be used as candidates for SO2 superior sensor with high sensitivity and selectivity at room temperature. Our studies not only reveal a new solution to modulate the electronic properties of 2D nanosheets, but also are helpful for designing novel boron nitride allotropes for expanding the possibilities of being as gas sensors as well as superior capturer of SO2 with high sensitivity.