In this study, adaptive inertia weight PSO (AIW-PSO) is applied to the path synthesis problem in order to compare the performance of an adaptive solution technique to the so far implemented ones and to investigate the effect of adaptability on the efficiency of the solution method. The search space is expanded by considering both circuits of the linkage as a candidate solution in formulating the objective function, and a new constraint is considered to account for the circuit defect. Moreover, a new refinement technique and a modification on a previously suggested one are introduced to improve the efficiency of the algorithm and a comparative study with previous results is also done. Results show that the implemented method performs better than other solution methods in all three case studies. AIW-PSO shows its capability to be used as a powerful method for solving design problems.