The aim of this paper is to accurately measure the thermophysical properties of diethyl ether and toluene by photo-thermal lens set-up. The thermal lens signal of these liquids was recorded and results show that the thermal lens formation process in these materials is in the order of milliseconds, while the thermal lens relaxation process is in the order of decaseconds. The thermal diffusivity and thermal conductivity of these solvents was measured at fixed laser energy of 90 mJ and temperature of 293 K. The deviation of the measured values from the literature values was less than 4.2%, which indicates the high accuracy of this optical set-up for measuring thermo-optical properties. Then, thermo-optical coefficient (dn⁄dT) of chloroform, diethyl ether and toluene was measured -6.31×10-4, -7.0×10-4, and -5.5×10-4 K^(-1), respectively. Also, the refractive index changes with the sample deposited heat (dn⁄dQ) for these materials were measured -0.407, -0.436, and -0.384 〖mm〗^3/J, respectively.
