Jialu Li (李佳璐) is a postdoc at the University of Maryland, College Park (UMD). She earned her B.Sc. from USTC in 2016 and completed her Ph.D. at UMD in 2023. Her research focuses on the molecular environment during star formation processes. Currently, she uses high spectral resolution MIR spectroscopy to investigate the Hot Core, an embedded phase during massive star formation. She also contributed to studies with Argus, a 16-pixel focal plane array for millimeter spectroscopy deployed on the GBT.The formation and evolution of massive stars are not well understood because they are deeply embedded. As the mid-infrared (MIR) dust continuum originates from the disk photosphere, the absorption line studies at MIR allow us to directly probe the properties of warm, dense gas in those regions. High spectral resolution absorption spectroscopy at MIR, therefore, enables a unique exploration of the physical conditions and organic inventory in the innermost regions of massive star formation while overcoming beam dilution issues present in submillimeter observations. In this talk, I will present high spectral resolution spectroscopy focused on the hot core region associated with the massive young binary W3 IRS 5 using IRTF/iSHELL (R~88,000) and SOFIA/EXES (R~50,000). I will present our findings from the analysis of hundreds of individual rovibrational absorption lines of CO and water. Furthermore, I will discuss how our high-resolution SOFIA study helps the analysis of low spectral-resolution JWST/MIRI observations, which is hampered by the blending of individual transitions into broad absorption features, optical depth effects, and line depth reduction due to partial coverage of the source.