An optimal synthesis method for a symmetrical seven-bar linkage’s kinematic design is presented in the paper. By avoiding singularities in an imposed workspace, the proposed synthesis approach computes the seven-bar linkage’s lengths of the links. The objective of this method is to minimize the robot’s horizontal size while simultaneously achieving the greatest range between the height of the mechanism in the minimum configuration (folded position) and maximum configuration (extended position). The optimal symmetrical seven-bar linkage is meant to be utilized for building a disinfection robot with folding mechanism, which will be capable of disinfecting the medical environment’s hard-to-reach locations.