Abstract 5-Methyl-and 5-phenyl-l, 2, 4-triazole-3-diazonium ions (IIIa, IIIb) react with undissociated phenol in diluted hydrochloric acid. At pH> 1 the reactions with phenolate ions become kinetically significant, their bimolecular rate constants approaching those of the diffusion-controlled reactions. At the same time, the diazonium ions are dissociated into the dipolar ions IIIb and IVb. At pH> 4 (for the phenyl derivative) and pH> 5 (for the methyl ...