Various amidinophenol derivatives (27-47) and their benzoates (4-26) were synthesized and evaluated for inhibitory activities against trypsin, plasmin, kallikrein, thrombin, Clr and Cls as well as in vitro complement-mediated hemolysis. 4-(β-Amidinoethenyl) phenyl 4-guanidinobenzoate (15) and 4-amidino-2-benzoylphenyl 4-guanidinobenzoate (26) were found to have potent inhibitory activities with IC50s of 9×10-8M (trypsin) and 2×10-7M (Cls) for the former and 3×10-8M (trypsin) and 2×10-7M (Cls) for the latter.