The synthesis and the pharmacological evaluation of benzisothiazole and benzimidazole tetrazolyl-and carboxyl-derivatives 1–6 are described. Structural modification was aimed at investigating the influence of two isosteric substituents (tetrazolyl-and carboxyl-) on the title benzofused heterocycles. The antiphlogistic, antipyretic and analgesic activities have been investigated in in vivo experimental models. Additional investigations have been ...