Surface modification of quantum dots (QDs) for improved photo and physicochemical properties is a topic of potential technological interest. Herein, we report on the synthesis of aggregation free 11-mercaptoundecanoic acid and tetraaniline (TA) capped CdS QDs with narrow size distribution (similar to 2.3 nm diameter), which are further characterized using UV-visible spectroscopy, photoluminescence spectroscopy, transmission electron microscopy and X-ray photoelectron spectroscopy. The TA capped CdS QDs show improved photoluminescence and photostability, which is attributed to the effective grafting of TA on CdS QDs through N-atoms, changing the surface chemical environment and facilitating charge transfer. (C) 2010 Elsevier B.V. All rights reserved.