Recently, much interest has been paid in the preparation and characterization of ternary semiconductors due to its potential applications in various fields [1-3]. ZnIn2Se4 (ZIS) is one among them that belongs to the AIIB2 IIIX4 IV defect chalcopyrite family. ZnIn2Se4 (ZIS) has been used as a buffer layer in the fabrication of CuInGaSe2 based solar cells [4, 5]. In the present work, nanocrystalline powders of ZIS was synthesized by simple and economic method, chemical precipitation and the properties are studied. Nanocrystalline ZIS powder was synthesized using 0.05 M equimolar aqueous solutions of zinc chloride (ZnCl2), sodium selenite (Na2SeO3) and indium chloride (InCl3) as precursors. The reaction temperatures (TR) of the chemical bath was varied in the range, 60 – 100 oC for a fixed reaction time of 60 min. The chemical and physical properties of the synthesized powders were analyzed using appropriate techniques. The energy dispersive X-ray analysis (EDAX) analysis revealed well defined peaks corresponding to Zn, In and Se in addition to low intensity O and Cl peaks. The ZIS samples prepared at TR = 100 oC had the atomic ratios 1:1.9:3.4 for Zn:In:Se elements respectively. The X-ray diffraction (XRD) analysis revealed that the synthesized powders were nanocrystalline and showed (112) plane as the preferred orientation. The crystallites size of the powder samples was varied in the range, 10 - 25 nm. Scanning electron microscopy (SEM) measurements revealed that the samples had a cauliflower like structure. The optical transmittance of the nanocrystalline powders was found to be >70% in the visible region and the evaluated energy band gap was 2.85 eV for the powder synthesized at a reaction temperature of 100oC. A detailed study of these results were presented and discussed.figureFig.1. XRD spectrum of ZIS powder. Fig. 2. SEM picture ZIS powder.