The synthesis and antiallergic activity of a series of novel benzothiophene-, benzofuran-, and naphthalenecarboxamidotetrazoles are described. A number of the compounds inhibit the release of histamine from anti-IgE stimulated basophils obtained from allergic donors. Optimal inhibition is exhibited in bermthiophenes with a 3-alkoxy substituent in combination with a 5-methoxy, 6-methoxy, or a 5, 6-dimethoxy group. Compound 13c (CI-959) also ...