The neglected tautomerism in “Study of the electronic effect and quantitative spectra predictions of o-methoxyanilineterminated monoazonaphthols: a combined experimental and DFT study” by Guoxun Zhu, Yan Lin, Wenxian Zhou, Huacan Song and Zhengquan Li, RSC Advances, 2023, 13, 33736

In the paper of Zhu and co-workers, cited in the title, the authors derived a protocol for the absorption spectra prediction is sulphonated azo naphthols assuming that they exist as single azo tautomers. However, as shown by the available experimental data and the calculations, performed in this note, the studied dyes exist almost solely in hydrazone tautomeric form, which unavoidably affects the conclusions and linear relations made in the original paper.