Herein, novel silver-based N-heterocyclic carbene (NHC) complexes bearing 2-(4-hydroxyphenyl)ethyl group were synthesized. Novel Ag(I)NHC complexes were synthesized from the 2-(4-hydroxyphenyl)ethyl-substituted benzimidazolium salts and silver oxide via in situ deprotonation method. The successful formation of all Ag(I)NHC complexes was proved by using H-1 NMR, C-13 NMR, FTIR spectroscopy, and elemental analysis techniques. In addition, their inhibitory effects have been investigated of these substances on acetylcholinesterase (AChE), alpha-glycosidase (alpha-Gly), human carbonic anhydrase I (hCA I), and human carbonic anhydrase II (hCA II) enzymes. It has been seen that all compounds have a better ability to inhibit compared with existing tried inhibitors. Among these, the best inhibitor against AChE enzyme is 1g (K-i : 9.54 +/- 0.98 mu M and IC50 : 17.40), and against alpha-Gly, 1c showed the highest effect (K-i 3.09 +/- 0.36 mu M and IC50 7.91). The best inhibitor against hCA I and hCA II enzymes are 1c and 1g compounds. For hCA I and hCA II, IC50 values were calculated as 17.85 and 9.06 mu M and K-i values were measured as 5.45 +/- 2.02 and 8.99 +/- 2.02 mu M, respectively.