The structure and electronic properties of liquid hydrogen cyanide (HCN) were investigated by carrying out sequential quantum mechanics/Born-Oppenheimer molecular dynamics. Focus was placed on the analysis of the polarization effects, dynamic polarizability and electronic absorption in liquid HCN. At the low-energy range, the HCN dynamic polarizability in the liquid is slightly increased in comparison with the gas-phase. Application of a 1-body approximation for the calculation of the vertical excitation energies indicates small (0.2 similar to 0.3) blue-shifts of the peak positions in the excitation spectrum of liquid HCN relative to the gas-phase HCN monomer. (C) 2012 Elsevier B.V. All rights reserved.