Highly luminescent GSH capped CdTe quantum dots (GSH-CdTe QDs) were prepared through a facile microwave (MW) aided wet chemical method. The mechanism of effective size control through the solvents is proposed. The Small angle X-ray scattering (SAXS) measurements show that the size dispersion of QDs can be precisely controlled through the selection of appropriate solvents. The high boiling point and high loss tangents were found to be effective in controlling the size dispersion in MW aided synthesis. The PL studies show that the sharpness of the emission peaks depends on the size dispersion. Keyword: GSH(Glutathione),Luminescent, Microwave (MW), Small angle X-ray scattering (SAXS), Quantum dots. I. Introduction QDs are being intensively used for producing solar panels (1,2) optoelectronic devices (3) and as fluorescent probes in bio-imaging and bio-sensing (4-6) among other applications. QDs have many advantages such as sharp emission spectra, higher chemical stability, tunable optical properties, photochemical stability and high quantum yields as compared to organic fluorescent material. These properties have broadened the range of applications of QDs in advance studies like protein trafficking (7) and in the treatment of cancer (8-10). Synthesis of QDs through high temperature thermal decomposition of organo-metallic compounds in high boiling point (B.P.) toxic organic solvents needs long reaction time and involves complex synthesis procedures producing QDs with poor biocompatibility (10-16). So there is a quest for new, simpler and efficient synthetic routes with alternative solvents. Present study focuses on synthesis of size controlled CdTe QDs through a fast and facile MW (17) aided wet chemical route. Glutathione (GSH)-capped CdTe QDs (GSH-CdTe) were synthesized under mild conditions. These GSH-CdTe QDs show similar optical properties as QDs synthesized using more complicated and expensive methods. MW irradiation is used as an efficient heating source which creates numerous nucleation sites in the solution, leading to the formation of homogeneous and size controlled nanoparticles (18). Synthesis of ZnS QDs using different polar solvents with high MW absorption is already reported (19).Moreover, the quantum confinement effects in QDs are size dependent and are instrumental in determining their optical properties, so the solvents were chosen carefully to get a better control over the particle size distribution of CdTe QDs. A mechanism to describe the role of solvents in controlling the size dispersion is proposed for a better understanding of the process. II. Experimental Present study describes a simple protocol for the aqueous synthesis of CdTe QDs using CdCl2, K2TeO3 and GSH.CdCl2 and K2TeO3 were used as the Cd 2+ and Te 2- sources. The interaction between these two compounds with microorganisms is well studied(20-23).Further, a biological thiol and a tri-peptide GSH works both as a reducing and capping agent for the aqueous synthesis of CdTe QDs(24), found in abundance in cells and are suitable for the stabilization of CdSe and CdTe QDs(25,26). Moreover, all of the operations could be performed in air avoiding the need for inert atmosphere due to the fact that K2TeO3 is air stable. The synthesis of CdTe QDs and their subsequent coating were as follows-