AbstractThis study's primary goal is to perform density functional theory and molecular docking simulation to determine decanal's structural stability and biological activity against proteins allied to breast cancer in order to validate its anti‐cancer potential. Initially, the drug‐likeness features of decanal was predicted and the outcomes confirmed that it is non‐toxic and follows Lipinski's rule. Through basis set 6‐311++G (d, p), the structural optimization was performed and molecular geometry was investigated. The FT‐IR and UV–Visible spectroscopic analysis was theoretically performed and validated via experimental analysis. The reactive surface of decanal was further investigated using a calculated molecular electrostatic potential surface. The molecular structural stability and bio‐reactivity of decanal was determined by using the HOMO‐LUMO energies and energy gap calculated is 6.215 eV. The charge distribution among the atoms of decanal was ascertained through the analysis of Mulliken and natural population distribution. To look at the decanal molecule's topological properties, electron localization function and localized orbital locator were used. The decanal's weak interactions were investigated via reduced density gradient assessment. The docking evaluation was performed against the proteins involved in breast cancer and the highest binding ability was calculated against the protein Bcl‐2 with the score of −6.5 kcal/mol. These theoretical findings will pave a way to understand the decanal's structural stability, reactivity and breast cancer inhibitory property and can be used as a drug candidate against tumor after in vitro and clinical evaluation.