The objective of “Design and Synthesis of Combinational Circuits Using Reversible Decoder in Xilinx” is to explore the use of reversible logic to implement various combinational circuit components—such as full adder, full subtractor, multiplexer, comparator, and decoder—with a focus on minimizing quantum cost, garbage outputs, and power dissipation by designing a reversible decoder using Fredkin gates and synthesizing the resulting circuits using Xilinx FPGA tools, demonstrating the advantages of reversible logic in low?power VLSI designs.