A wide range of water-soluble quaternary ammonium acylhydrazones based on catecholaldehyde were synthesized and characterized using NMR, IR spectroscopy, and elemental analysis. The total antioxidant capacity of the acylhydrazones discussed herein was estimated via coulometric titration with electrogenerated bromine. Pyridinium derivatives - exhibited the highest antioxidant capacity. Quaternary ammonium acylhydrazones demonstrated high antimicrobial activity against Gram-positive bacteria, including methicillin-resistant strains. Furthermore, low hemo- and cytotoxicity and the absence of a negative effect on the hemostatic system were confirmed for the studied compounds. According to the results of a CV test, the antimicrobial effect of the most active acylhydrazones, namely, , , , and , is associated with the destruction of the bacterial cell wall. High or moderate activity against phytopathogens of bacterial origin was observed for all the acylhydrazones evaluated. Anti-aggregation activity was observed for compound ; the extent was 1.6-fold greater than that exhibited by acetylsalicylic acid. On the contrary, compound exhibited a pro-aggregant effect (with a 6.3% increase in platelet aggregation and a >15% decrease in the latent period compared to the control). Thus, the data obtained can be considered the basis for further pharmaceutical development of these effective drugs with antithrombotic and hemostatic potential.