New Schiff base-bearing thiosemicarbazones (1-13) were obtained from 4-hydroxy-3,5-dimethoxy benzaldehyde and various isocyanates. The structures of the synthesized molecules were elucidated in detail. Density functional theory calculations were also performed to determine the spectroscopic properties of the compounds. Moreover, the enzyme inhibition activities of these compounds were investigated. They showed highly potent inhibition effects on acetylcholinesterase (AChE) and human carbonic anhydrases (hCAs) (K-I values are in the range of 51.11 +/- 6.01 to 278.10 +/- 40.55 nM, 60.32 +/- 9.78 to 300.00 +/- 77.41 nM, and 64.21 +/- 9.99 to 307.70 +/- 61.35 nM for AChE, hCA I, and hCA II, respectively). In addition, molecular docking studies were performed, confirmed by binding affinities studies of the most potent derivatives.