Infrared laser spectroscopy has been used to characterize imidazole (IM) dimer and its water complexes formed in helium nanodroplets. Two different complexes of (IM)(2)-H2O have been identified in the free OH stretching spectral region of 3710-3755 cm(-1). The assignment of the infrared vibrational bands of the clusters is aided by ab initio calculations. Vibrational transition moment angles (VTMAs) provide conclusive assignments for the complexes studied in this work. (C) 2009 Elsevier B. V. All rights reserved.