Solid ZnSe quantum dots (QDs) have been prepared via chemical route. The QDs have been characterized by X-Ray Diffraction (XRD), Transmission Electron Microscopy (TEM), Photoluminescence (PL) and Ultraviolet- Visible Spectroscopy (Uv-Vis). The QD sizes were found to vary from 2.5 to 9.5 nm. The XRD measurement reveals an increase in the interplanar spacing in QDs as compared to their bulk counterpart. This observation is further supported by Rietveld analysis which establishes the formation of single phase zinc blende ZnSe QDs and confirms 3.9% lattice expansion. Calculations based upon the thermodynamical theory yield 8.7% concentration of vacancies due to the lattice expansion.We observe various peaks in the PL spectra which may arise either due to the QD size variations or the defects due to the vacancies.