The paper reports the synthesis, characterization and photochemical properties also in the presence of selected metal ions of an aza- and oxa-aza- macrocyclic series based on 2,3-diphenylquinoxaline moiety.
In my opinion, despite the interesting content of the paper, it results too long and verbose in many parts and so difficult to read.
I’d advise Authors to short it shortening some parts but, above all, eliminating the “Metal Ion complexation chapter”. This and the relative conclusions merit a more detailed investigations through a dedicated paper, widening the studies not only to the two ligands here reported, both belonging to the N2CnOxQ series, but also to ligands of the other NyCnQ series. Otherwise, in this form, the results and discussion for the metal ion coordination are incomplete and disputable to be the real criticism of the paper. For example, I have doubt about the studies in acetonitrile to evaluate the stability constants because carried out without fixed ionic strength, percentage of water and controlled pH, taking also into account that the salts used contain water molecule; a preliminary studies of acid-base properties of ligands are necessary to validate the photochemical behavior, this also considering the acid properties of many salts investigated and in particular Al(III) and Cr(III) cations; it is interesting the CHEF effect of Cu(II) that was not observed with Zn(II) and the proposed model should be better validate to be safe; these are only few examples to support the advice to remove or deeply revise this part.
In other words, except for the metal coordination part, I found the work well carried out, reporting many interesting aspects and it could be suitable for the publication after the elimination of the above criticism otherwise, it needs a major revision focusing the attention on the metal coordination chapter.
Minor points:
- in Scheme 1 first imagine from the top; a comma ot the word “or” should be inserted between the draw of the two L, BINAP and PhPF-tBu
- page 6 of the pdf; in the Synthesis’s discussion: Authors could specify in what the modification to obtain 3 consist
- page 9 of the pdf, right column: “For example, a 60 nm red shift is observed between the emission maxima of N3C4Q and N2C10O2Q in dichloromethane (DCM).” Please, check the data, there is not correspondence in Table 1

Thank to Authors to have revised the paper accordingly to suggestions of the Reviewers; in my opinion, the paper has been improved and deserve publication