A novel cost effective design of Programmable Logic Array (PLA) is proposed by recursive use of XOR gate, which is used to design 2×4, 3×8 and 4×16 decoders. The 4×16 decoder is coupled with an OR-Array to implement the proposed PLA using Quantum-dot Cellular Automata (QCA). The design is made effective by substantially reducing QCA wire crossing and cell count. A comparative study shows the minimization of cell count and clock-cycle delay of the XOR and Decoders. The PLA is utilized to design an efficient and delay effective 2 bit full adder.