Single crystals of tetra thiourea cobalt chloride (TTCoC) having dimension of 25 mm x 2 mm x 7 mm were grown by slow evaporation solution growth technique. The structural perfection of the grown crystals was analyzed by high-resolution X-ray diffraction (HRXRD). The mechanical property of the grown crystals has been analyzed by Vicker's microhardness method. The dielectric constant measurements were carried out and the nature of variation of dielectric constant epsilon(r) and dielectric loss D were studied and reported. (C) 2008 Elsevier B.V. All rights reserved.