Synthesis and biological activity of a variety of 3- and 6-substituted 1H-pyrrolo[2,3-b]pyridine (7-azaindole) derivatives are described. Many of the synthesized 7-azaindoles exhibited considerable fungicidal activity toward Pyricularia oryzae, a fungus which causes rice blast, in vivo. When quantum parameters of the tested 7-azaindoles were evaluated by semiempirical molecular orbital calculations, a relationship was observed between the activity and the calculated ionization potentials of the 7-azaindole derivatives. Keywords: 1H-Pyrrolo[2,3-b]pyridine; fungicidal activity; ionization potential; rice blast