Abstract <p>Synthesis of the 2,6-diphenyldpiperidin-4-one derivative of title compound 4,4a,5,6,7,8-hexahydro-4<i>a</i>-methyl-2,5,7-triphenyl-2<i>H</i>-pyrido[4,3-<i>d</i>][1,3]oxazine (HMTPO) is developed using the reaction of 4-hydroxy-3-methyl-2-butanone, benzaldehyde, and ammonium acetate in ethanol as a solvent. The molecular structure of HMTPO is determined by single crystal X-ray diffraction. The chemical structure is confirmed by employing IR, ¹H NMR, ¹³C NMR, and mass spectral data. To gain deeper insight into the bonding interactions within the compound, Hirshfeld surface analysis and two-dimensional fingerprint plots are conducted. The findings reveal that the Hirshfeld surfaces are predominantly influenced by H⋯H and C⋯H contacts, highlighting the significant role these interactions play in the compound’s overall stability and structural configuration.</p>