The solubility of zinc cadmium thiocyanate, ZnCd(SCN)(4) (ZCTC) crystal has been studied by changing the pH values of the growth aqueous solutions. The crystallization habit of ZCTC crystal in aqueous solution has been investigated by means of the micro-crystallization. Both the solubility and crystal habit are discussed by a careful analysis of the hydrogen-bond network formed between the solvent and the solute. The crystal exhibits good crystallization morphology when the pH values range from 3 to 5. Large single crystals of high optical-quality have been easily grown from aqueous solutions under the two considerations. The corresponding spectral characterizations of the crystals grown at different pH values have also been performed and discussed. The second-order nonlinear optical coefficients of high optical-quality ZCTC crystal are determined. (C) 2004 Elsevier B.V. All rights reserved.