Molecular properties of the OCS-C2H2 van der Waals complex are studied in detail in order to explore the possibility of formation of three isomers of the complex and to verify the experimental findings. Both dispersion-corrected and -uncorrected double hybrid density functional theories with correlation consistent triple zeta basis set are used to investigate the complex. The results obtained by the dispersion corrected density functional method, mPW2PLYP-D, agree very well with the experimental values. The Symmetry Adapted Perturbation Theory (SAPT) is applied to study the interaction. (c) 2012 Elsevier B.V. All rights reserved.