AbstractSurface modification as well as size control of CdS colloids in acetonitrile has been achieved with mercaptoethylamine (MEA). The CdS emission yield increases as it interacts with the surface modifier. A decrease in the hole‐trapping yield was observed in optically excited CdS colloids which were modified with MEA. Use of such surface modifiers in bridging a semiconductor colloid with a gold colloid has also been demonstrate