Symmetric coupling of a hardly forming multifunctional diazonium salt of low basicity melamine with phenols is performed with difficulty with a very slight decline in the higher phenol acidity. The azopyrogallol derivative maintains the melamine D-3h symmetry explicit in the H-1-NMR spectrum showing the azo substituents in the same magnetic environment with the phenyl ring protons shown in a sharp (6.30 ppm) resonance and the phenolic protons in a broad (8.70 ppm) signal. This weakly deshielded simple spectrum of singlet signals is assigned to a quinonoid structure, particularly when the broad signal characteristic of phenolic proton exchange is considered. The broad signal sharpens and shifts downfield indicating a progressing association for the other azophenol derivatives. The quinonoid pi-pi* transition wavelength also falls with the association. The quinonoid structure seems to decline with association in favor of a more mesomeric benzenoid structure that stabilizes the pi-orbital versus the pi*-orbital into a shorter wavelength pi-pi* transition. Variable temperature FT-IR spectroscopy compares the effects of proton mobility and H-bonding association on the mesomeric structure of these azo derivatives in the more dense solid state. Consistent with the quinonoid structure, azopyrogallol shows high C-N and C-O but low N-N and O-H bond order that invariably changes with proton mobility and H-bonding association. At variance with azopyrogallol inclining to the quinonoid structure of high proton mobility, azoquinol lacks such a property so that it leans to the benzenoid structure where rotation around the N = N bond is difficult that allows for a possible distortion in the dense solid state. The other azo derivatives arrange with a structure shifting with variation in the proton mobility: azopyrogallol similar to azocatechol similar to azophenol similar to azoresorcinol similar to azoquinol with quinonoid [hydrazo] form and proton mobility at the azopyrogallol end and benzenoid [azo] form and H-bonding association at the azoquinol end.