beta-Lactams are pharmacologically important compounds because of their various biological uses, including antibiotic and so on. beta-Lactams were synthesized from benzylidene-inden derivatives and acetoxyacetyl chloride. The inhibitory effect of these compounds was examined for human carbonic anhydrase I and II (hCA I, and II) and acetylcholinesterase (AChE). The results reveal that beta-lactams are inhibitors of hCA I, II and AChE. The Ki values of beta-lactams (2a-k) were 0.44-6.29 nM against hCA I, 0.93-8.34 nM against hCA II, and 0.25-1.13 nM against AChE. Our findings indicate that beta-lactams (2a-k) inhibit both carbonic anhydrases (CA) isoenzymes and AChE at low nanomolar concentrations.