The fluorescence excitation spectra are recorded for jet-cooled dual hydrogen-bonded 3-methyl-7-azaindole dimer (3MAI)(2)-hh and deuterated dimers (3MAI)(2)-hd and (3MAI)(2)-dd near the electronic origin region of the S-1-S-0 transition, where hd and dd indicate the deuteration of an imino hydrogen and two imino hydrogens, respectively. A single origin is detected in the spectra of (3MAI)(2)-hh and (3MAI)(2)-dd, whereas two electronic origins separated by 13 cm(-1) are detected in the spectrum of (3MAI)(2)-hd. The excited-state double-proton transfer (ESDPT) occurs in (3MAI)(2)-hh, while (3MAI)(2)-hd and (3MAI)(2)-dd undergo excited-state proton/deuteron transfer and excited-state double deuteron transfer, respectively. In (3MAI)(2)-hd, the excitation is localized on either the 3MAI-h or 3MAI-d moiety. The localization of the excitation is explained by a weak coupling of the excitonic states of (3MAI)(2)-hh and (3MAI)(2)-dd. The effective symmetry of the lowest excited state of (3MAI)(2)-hh and (3MAI)(2)-dd belongs to the C-2h point group, while that of (3MAI)(2)-hd belongs to the CS point group. The vibronic patterns in the excitation spectra of the (3MAI)(2) dimers is very similar to those of the 7-azaindole dimers, indicating that the methyl substitution provides little effect on the shape of the ESDPT potential.