Syntheses were conducted of novel benzimidazole derivatives that suppress histamine release from mast cells, inhibit 5-lipoxygenase, and possess antioxidative action. Among the compounds synthesized, 1-[2-[2-(4-hydroxy-2, 3, 5-trimethylphenoxy) ethoxy] ethyl]-2-(4- methyl-1-homopiperazino) benzimidazole (22) potently suppressed histamine release from rat peritoneal mast cells triggered by the antigen-antibody reaction, inhibited 5- ...