CdZnS quantum dots (QDs) with systematically varied Zn content (from 0 to 100%) are formed in an organic matrix using the Langmuir–Blodgett technique. Annealing of the QD structures leads to a removal of the organic matrix and an increase in the Zn content for free-standing CdZnS QDs. After annealing, the size of QDs as determined from UV–vis absorption experiments is in good agreement with electron microscopy measurements. Analysis of UV–vis absorption and Raman scattering data demonstrates strong changes in the content of the CdZnS QDs upon annealing. A model of the process of QD formation is developed using the precipitation model and is found to adequately describe the experimental results.