Here, the synthesis, spectral and the structural studies of 2-hydroxyethyl substituted N-heterocyclic carbene (NHC) precursors and the enzyme inhibition activities of the NHC precursors were investigated against the cytosolic carbonic anhydrase I and II isoenzymes (hCA I and hCA II), and xanthine oxidase (XO). The IC50 values of NHC precursors against these enzymes were determined by spectrophotometric method. The spectra of new NHC precursors have been obtained by using H-1 NMR, C-13 NMR, FTIR spectroscopy and elemental analysis techniques. The structure of a new NHC precursor was established by using single-crystal X-ray diffraction method. The results of inhibition experiment indicated that all 2-hydroxyethyl substituted NHC derivatives showed remarkable inhibition activity toward hCA I, hCA II and XO. The range of IC50 values for hCA I, hCA II and XO inhibition was determined as 0.1565-0.5127, 0.1524-0.5368 and 1.253-5.342 mu M. Especially, trimethylbenzyl derivative of 2-hydroxyethyl substituted NHC precursor has demonstrated high inhibition effect on all studied enzymes due to steric bulk of this substituent. (C) 2019 Elsevier B.V. All rights reserved.