Geometries, stabilities, NBO, vibrational spectroscopy and NICS of (BN)₂₅ clusters were optimized in the framework of density functional theory (DFT) through the use of B3LYP hybrid functional associated with 6-31G(d) basis sets. We found that (BN)₂₅ clusters is stable due to its large average binding energy and energy gap. Charge transfer and s, p hybridization between adjacent B and N atoms are confirmed by NBO analysis. Many vibration peaks are found in infrared spectrum and Raman spectra. Negative nucleus independent chemical shifts(NICS) indicate that BN clusters have aromatic properties.