In recent years, a large number of nano-size semiconductors have been researched for their potential applications in photovoltaic cell, optical sensor device and photocatalysts. Nano-size semiconductor particles reveal many interesting properties due mainly to their sizedependant optical properties. In this sense, many kinds of nanomaterials have been prepared, such as CdS, CdSe, CuS, and other composite materials. However, most of them were prepared with toxic reactants and/or complex multistep reaction process. To overcome such problems and to apply multilayered semiconductor nanoclusters, a lot of core/shell type nanocrystals are extensively studied through various methods, such as microwave and sonochemistry. The sonochemistry is an application of sonoluminescence (SL) which is a light emission phenomenon associated with the catastrophic collapse of a gas bubble oscillating under an ultrasonic field. The intense local heating and high pressure inside the bubbles and liquid adjacent the bubble wall from such collapse can give rise to unusual effects in chemical reactions and the sonochemical processing has been proven to be a useful technique to make novel materials with unusual properties. The estimated temperature and pressure in the liquid zone are about 1000 C and 500 bar, respectively, which make a high-energy chemical reaction possible. In case of multibubble sonoluminescence (MBSL) condition, a lot of transient bubbles can be generated by the irradiation of high intensity ultrasound in aqueous solution, providing unusual reaction conditions. In fact, methylene blue (MB) which is one of typical textile dyestuffs was degraded very fast at the MBSL condition while the MB was not degraded under simple ultrasonic irradiation. In this study, TiO2 nanoparticles were tried to be coated with CdS through a one pot reaction under MBSL condition, which are very likely to be useful for the development of inorganic dye-sensitized solar cells. Figure 1 shows an experimental apparatus for MBSL with a cylindrical quartz cell, into which a 5 mm diameter titanium horn (Misonix XL2020, USA) is inserted. This system was operated at 20 kHz and 220 W. The solution in the test cell was kept at 1.4 atm with argon gas and the temperature of the solution inside the cell was kept to around 40 C by a water bath. These were found to be optimal conditions for the process. Experimental details