The fluorescence excitation and dispersed fluorescence spectra of jet-cooled 4-dimethylamino-7-azaindole dimer are recorded to investigate the effect of a substitution of a dimethylamino group into the 4-position of the hydrogen atom of the 7-azaindole on the excited-state double proton transfer (ESDPT). The substitution of the dimethylamino group drastically suppresses the ESDPT reaction.