2-(4-Imidazoyl) hydrocinnamic acid (1) and its congeners (2–4) having different length of alkyl chain spacers between the imidazole ring and the α-carbon to the carboxylate of 1 have been designed, synthesized and evaluated as inhibitors for carboxypeptidase A to show that they are competitive inhibitors for the enzyme. Inhibitor 1 was most potent having the Ki value of 0.8 μM. The present study demonstrates that imidazole ring is an effective ...