In the present study, 2-(p-tolyl)-2,3-dihydro-1H-perimidine (TDHP) is synthesized from 1,8-naphthalenediamine and 4-methylbenzaldehyde by embedding a one-carbon unit between the nitrogen followed by ring closure using green chemistry approach. ¹H NMR and ¹³C NMR spectral techniques were used to validate the structure of the TDHP. The synthesized perimidine TDHP is studied using density functional theory (DFT) to provide valuable insights into structural, chemical, and thermochemical study.The structural and chemical properties of TDHP were computed using the DFT method on the B3LYP/6-311G(d,p) basis package. Bond lengths were predicted from the optimised molecular structure, and the physical and chemical properties of the molecules were inferred as a consequence. The HOMO and LUMO are computed, and quantum chemical parameters are determined using electronic energies. The calculated HOMO-LUMO energy gap is 4.25 eV indicating charge transfer phenomenon within the molecule. The electron density and chemical behaviour of the TDHP was predicted using Mulliken atomic charges and the molecular electrostatic surface potential plot.Amongst all carbon atoms, the C8  carbon as more positive and C27 as more negative carbon atoms. The high global electrophilicity index suggests electrophilic character of the TDHP.The harmonic vibrational frequencies were used to measure total energy, total molar entropy, and molar heat capacity.