With a careful analysis, it is clear that the induced large bandgap of FBNF tends to create the optical spectra absent in the IR, and in the VR, and only appear around the UV regions from 4.61 eV to 22.10 eV. The multiple oscillatory peaks in the real and imaginary dielectric curve demonstrate the rigorous inter-band transitions. This supports FBNF to possess the highest absorbance (up to 9.01×10 5 -1 ) with small electron energy loss in in-plane direction demonstrating an outstanding optical response. Plus, the strong optical anisotropy enriches its optical quality to make it a proper optoelectronic material. It is worth mentioning that, similar optical behavior is observed in the fluorinated SnC monolayer calculated by using first-principle DFT calculations .