The study delivers a detailed and innovative examination of the structural, electronic, optical, and thermoelectric characteristics of silicon phosphide (SiP) nanosheetsan emerging two dimensional (2D) material with significant promise for next-generation technologies. Using advanced first-principles calculations grounded in Density Functional Theory (DFT), we report for the first time that monolayer SiP features a unique combination of a direct, tunable bandgap, highly anisotropic electronic characteristics, and exceptional carrier mobility. These properties position SiP as an excellent candidate for cutting-edge optoelectronic applications, including blue light-emitting diodes and photodetectors. Its strong optical absorption across the visible to near-ultraviolet range, along with high photothermal conversion efficiency, further highlights its potential in advanced photonic systems. Notably, the feasibility of mechanical exfoliation supported by SiP’s low cleavage energy suggests a practical route for synthesizing high-quality nanosheets. Furthermore, the material’s promising thermoelectric performance indicates untapped potential in energy harvesting and conversion technologies. Overall, this work identifies SiP nanosheets as a versatile and innovative material platform, poised to drive progress in electronics, optoelectronics, and sustainable energy solutions.