In this study, the synthesis and theoretical calculations of dithiocarbazate derivative, benzyl 3-[(E,E)-3-phenylprop-2-enylidene]dithiocarbazate (BPED) was carried out using density functional theory (DFT) with Becke-3-Lee-Yang-Parr (B3LYP) function at 6-311G (d) basis set. The geometry optimization of trans-cis and cis-trans configurations of the title compound reported. Whilst, comparison studies of infrared (IR) spectra of the title compound between experimental and theoretical of different conformations (cis-trans and trans-cis) are presented in this contribution. The molecular orbital (MO) theory analysis of BPED has been interpreted to investigate the more stable conformation of BPED from the energy band gap (Δ EHOMO-LUMO ) differences between highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO).
