The synthesis of CdSe quantum dots (QDs) from a single source precursor is a known way to form a nanocomposite by its thermal decomposition. Recently, some of them have been used to grow QDs by direct laser patterning. Here, the authors report the study of the formation of the CdSe QDs starting from the decomposition of the 2-(N,N-dimethylamino)ethylselenolate of cadmium dispersed in a polymethylmethacrylate film induced both by heating and laser patterning. The formation of the CdSe QDs under annealing at 150 °C is studied as a function of the precursor concentration and molar ratio with respect to two different QD ligands such as oleic acid and oleylamine. The photoluminescent spectra of the formed nanocomposite show that the oleic acid induces the formation of the direct bandgap, while oleylamine shows only a broadband emission. The laser patterning of the film was carried out with a UV laser (355 nm) with a pulse frequency of 40 kHz and a fluence of 1.06 J/cm2. The resulting patterned areas were characterized by a fluorescence microscope showing the formation of a photoluminescence path only when the ligands were present, suggesting the formation of the functional (photoluminescent) QDs.