One of the primary strategies towards the enhancement of energy efficiency through the incorporation of renewable energy is solar-assisted binary vapour power cycles optimization. The focus of this study will be two configurations: an External Source-Based Binary Vapour Power Cycle and an improved ExSRBVP configuration, containing a reheating mechanism. Thermodynamic models were created by the authors for various parameters analysis—turbine pressure, temperature, and absorber pressure on first law efficiency. The results show that the ExSRBVP cycle has better performance, and higher pressures and temperatures in the topping cycle lead to a higher efficiency. This happens especially at absorber pressures of 5–15 bar. The improvement in efficiency is due to the increase in enthalpy and energy recovered by the bottoming cycle, thus compensating for the mass flow rates that have decreased. Data table and figure show that while the ExSBVP setup has an enormous efficiency if optimized, the ExSRBVP setup does improve energy significantly due to reheating. This, in turn, opens an opportunity for integration of solar power with some advanced techniques in thermodynamics to have efficiency in generating power without jeopardizing its sustainability. Integration with further renewable resources for enhanced robustness and longer-term sustainability is what research should explore in the future. The current work will therefore contribute towards the development of renewable energy technology in advancing eco-friendly and efficient power generation systems that are environmentally and economically beneficial.