A numeric symbolic solution technique is introduced for the simulation of ac impedance response of electrochemical devices. The proposed method is numerical in the spatial coordinates and yields a closed form symbolic solution in the system parameters. The system of algebraic equations obtained by the spatial discretization is written in matrix form and solved symbolically. Although this method is capable of simulating ac impedance data for systems with multiple coupled partial differential equations, the method and its advantages over classical methods are illustrated using diffusion in a planar electrode. (c) 2006 The Electrochemical Society.