Use of various organic fluids in Organic Rankine Cycle is investigated as hybrid cycle with Gas Turbine (GT/ORC). Analysis presents a first and second law of thermodynamics for fourteen Organic fluids. Using the first and second laws of thermodynamics, the performance of an ORC can be evaluated under diverse working conditions for different working fluids. Superheating for some organic fluids performed are investigated. Viable results have been obtained for R245fa, propane and R152a ORC combined cycles, with reasonably high global efficiencies for low temperatures and for temperature more than 100 °C results demonstrate that GT/ORC using R113 shows the maximum efficiency.