Molecular and Vibrational structure of 2A5CB were analyzed with the aid of density functional theory at B3LYP/6- 31G(d, p) and 6-311G(d, p) level basis sets. Optimized geometrical structures, harmonic vibrational frequencies, intensities, reduced mass, force constants and depolarization ratio have been computed by the B3 based (B3LYP) density functional methods The calculation results also show that the synthesized molecule have microscopic nonlinear optical (NLO) behaviour with non zero values. The Fourier transform infrared (FT-IR) spectroscopic studies were performed for identifying different functional groups present in the compound and compared with the calculated vibrational frequencies. The important thermodynamical parameters were also reported. The simulated infrared spectrum of the title compound shows good agreement with observed spectra.