Single crystals of pure and doped bis(thiourea) cadmium chloride (BTCC) belonging to semiorganic nonlinear optical materials are grown by slow evaporation technique. The lattice parameters of the grown crystals are determined by single-crystal XRD. Single crystal XRD studies reveal that the incorporation of metallic dopants has not changed the structure of the parent crystal. The TGA traces of doped BTCC crystals indicate a marginal increase in the thermal stability of the samples. The response of dielectric constant in the frequency region of 500 Hz to 500 kHz has been investigated and the influence of metal substitution on the dielectric behaviour has been reported. Photoconductivity studies of pure and doped BTCC crystals revealed the positive photoconducting nature. Optical absorption studies indicate the low percentage of absorption of doped crystals in the visible region, thereby confirming the enhancement of NLO property. (c) 2005 Elsevier B.V. All rights reserved.