A novel Schiff base ((E)-methyl-3-(3,5-di-tert-butyl-2-hydroxybenzylideneamino)-4-methylbenzoate (MDM), C24H31NO3) at phenol-imine form with the O-HMIDLINE HORIZONTAL ELLIPSISN intra-molecular hydrogen bond was synthesized. Its structural and spectroscopic characterizations were performed by using experimental (single crystal X-ray diffraction, Fourier transform infrared [FT-IR], NMR chemical shift, and UV-vis spectroscopies) and theoretical (DFT/B3LYP/6-311+G[2d,p] computational level) methods. X-ray diffraction investigation shows that the MDM crystallized in phenol-imine form with O-HMIDLINE HORIZONTAL ELLIPSISN intra-molecular hydrogen bond. Detailed investigations of the presence and nature of the inter-molecular contacts within solid state crystal packing form of MDM were examined by Hirshfeld surface analysis. The intra-molecular electronic transitions in the compound were investigated and determined by UV-vis electronic absorption wavelengths and FMOs analyses. The structural, vibrational, and NMR chemical shift analyses of azomethine (-CH(sic)N-) and phenolic hydroxyl (-OH) groups in MDM supported its phenol-imine structural formation.