The colloidal synthesis of CdSe/ZnSe core/shell quantum dots (QDs) under nitrogen gas flow is presented in this study. The optical, morphology and structural properties of CdSe/ZnSe core/shell QDs are varied by changing the growth temperature and the cadmium source (Cd2+). The Fourier transform infra-red studies validate that CdSe/ZnSe QDs capped with functional 􀀀 COOH groups were formed. The morphological and composition studies conducted using high resolution transmission microscope, selected area electron diffraction andenergy dispersive spectroscope confirmed the formation of pure and mono-disperse QDs while photoluminescence and ultra-violet visible spectroscopy displayed their improved fluorescent properties. Caco-2 cell line was cultured from colon cancer and cytotoxic studies were conducted to test for cell viability of various capped 3-MPA CdSe/ZnSe QDs at various concentrations. The formed CdSe/ZnSe QDs prominently bear the zincblende structure with their particle size lying well below the Bohr excitation radii. Their hydrophilic nature and the availability of functional groups on the CdSe/ZnSe QDs makes them excellent potential labeling and therapeutic agents for the colon cancer disease diagnosis.