Abstract: Over 300 molecular species have been identified in the interstellar medium and circumstellar shells, revealing a diverse landscape of chemical complexity. Protostellar objects exhibit a wide variety of both simple and complex organic molecules, intricately linked to their physical properties and evolutionary stages. High-mass stars play a pivotal role in shaping their surroundings, acting as potent sources of radiative and mechanical feedback that significantly influence YSOs. Furthermore, these celestial bodies serve as unique stellar laboratories, providing insights into astrochemical processes within molecular clouds. Analyzing the millimeter and submillimeter spectra of high-mass stars offers crucial clues to the formation of numerous complex organic molecules, enhancing our understanding of the chemical intricacies within YSOs.  In this talk, I will discuss the observational results from a large sample of high-mass YSOs and elaborate on how chemical diversity depends on the physical properties of the sources. I will also present astrochemical modeling results to describe the chemical evolution of many species and how they can be used to infer the physical properties of YSOs. By summarizing the current state of observational studies and astrochemical models focused on high-mass YSO-forming regions, this presentation aims to elucidate the processes through which chemical complexity is attained in diverse YSOs.