Single crystals of zinc cadmium thiourea complex Zn0.625Cd1.375(CS(NH2)(2))(9.)4(SO4) (ZCTS) are grown by slow evaporation of aqueous solution containing zinc sulfate, cadmium sulfate and thiourea in the ratio 1:1:6. Crystal composition as determined by single crystal X-ray diffraction analysis reveals that it belongs to the monoclinic system with space group P2(1) and cell parameters are a=13.263(5) angstrom, b=11.886 (5) angstrom, c=27.215(5) angstrom, alpha=gamma=90.000(5)degrees, beta=96.586(5)degrees, V=4262(3) angstrom(3) and Z=2. The presence of zinc and cadmium in the final product is further confirmed by inductively coupled plasma (ICP), atomic absorption spectroscopy (AAS) and energy dispersive X-ray spectroscopy (EDS). The vibrational patterns in FT-IR are used for identifying the material and the thermal analysis by TG/DTA indicates the stability of the mixed crystal. The surface morphology changes of the mixed crystal are studied by scanning electron microscopy (SEM). High transmittance in the visible region is observed with a lower optical cut-off at similar to 260 nm. The change in intensity patterns in XRD profiles indicates lattice distortion. The relative second harmonic generation (SHG) efficiency measurements reveal that the mixed crystal has a superior activity than that of tris(thiourea)zinc(II) sulfate (ZTS). (c) 2013 Elsevier B.V. All rights reserved.