CsB3O5 (CBO) single crystal, up to 47 x 45 x 41 mm(3) in size and 221 g in weight, has been grown by the top-seeded solution growth (TSSG) method from Cs2O-B2O3-MoO3 system. Thermophysical properties including the specific heat, thermal diffusion, thermal conductivity, and thermal expansion were systematically investigated for the first time. The specific heat was measured to be 0.512-0.796 J g(-1) K-1 in the temperature range from 25 to 300 degrees C. According to the measured thermal diffusion coefficients, the thermal conductivities along the a-, b-, and c-axis at 30 degrees C were calculated to be kappa(a) = 1.43 W m(-1) K-1, kappa(b) = 2.50 W m(-1) K-1, and kappa(c) = 1.51 W m(-1) K-1, respectively. CBO exhibits strongly anisotropic thermal expansion behavior, and the mean thermal expansion coefficients in the temperature range from 25 to 500 degrees C are alpha(a) = 46.77 x 10(-6)/degrees C, alpha(b) = 18.39 x 10(-6)/degrees C, and alpha(c) = 3.80 x 10(-6)/degrees C. The measured dielectric constants, epsilon(a), epsilon(b), and epsilon(c), are 8.41, 8.31, and 8.13, respectively. Crown Copyright (C) 2012 Published by Elsevier B.V. All rights reserved.