Nanocomposites of CdS nanocrystals (NCs) embedded in a polyvinyl pyrrolidone are grown using one-step chemical bath deposition technique. While this method eliminates an additional step for the growth of NCs, it also leads to the formation of nearly monodispersive CdS NCs as indicated by absorption, reflection, and photoluminescence spectroscopy. Further, scanning electron microscopy, energy-dispersive spectroscopy, and transmission electron microscopic investigations reveal the formation of nearly monodispersive CdS NCs (similar to 6 to 10 nm) embedded in PVP spheres of sizes similar to 100 to 600 nm. Systematic study of variation in Cadmium acetate (Cd ion source), Thiourea (S ion source), PVP concentration, deposition time, and heating/cooling cycles elucidates the co-operative growth mechanism for CdS-PVP nanocomposite. The experimental observations of this study are corroborated with existing theoretical simulations for nanocomposite growth, which explicates that collapse of PVP into a sphere is crucial to inclusion of only nearly monodispersive CdS NCs. Important insights obtained from this work give control on the growth of nearly monodispersive CdS NCs embedded in PVP, using a simple and inexpensive growth technique.