Some new coloured monomers having electron-withdrawing groups were synthesized from 2-methylresorcinol, and their structures were confirmed by 1 H-NMR, IR, and combustion analyses. The effects of substituents in the diazo components on colour and NMR properties were examined. The effects of solvent polarity on the chemical shifts in NMR spectra were also determined. Explanations for the observed effects are presented.