In the present work, we use an open-photoacoustic-cell (OPC) operating at high frequency to measure thermal properties of two-layer system samples. Photothermal deflection technique is also employed to measure the samples. The effective thermal diffusivity measured using the OPC method is interpreted using the concept of effective thermal resistance for a series two-layer system. The results show the reliability of the photoacoustic method for a complete thermal characterization of the samples. In addition, by varying the sample effective thickness, the thermal diffusivity and conductivity of each layer are precisely determined. The effective thermal diffusivity, thermal conductivity, and specific heat of a porous catalyst layer (thickness varying from 13 to 53 μm) deposited on an aluminum foil (53 μm in thickness) were thus measured and found to be (3.7+-0.3)x10−³ cm² / s, (7.5+-0.7)x10−³ W/cm K, and (1.6+-0.2) J /gK, respectively. ; peer reviewed: yes ; NRC Pub: yes ; system details: machine converted author identifier PE to PID, February 2012