Is Molecules (MDPI) Predatory? A Practical Verdict

Molecules was founded in 1996, making it one of the earliest open-access chemistry journals and one of MDPI's longest-running titles. Its editorial board exceeds 1,700 members, all working chemistry researchers at recognized institutions.

It is indexed in SCIE (Q2 in Chemistry, Multidisciplinary at rank 75/239; Q2 in Biochemistry and Molecular Biology at rank 82/319), Scopus (Q1 in Analytical Chemistry, Organic Chemistry, Pharmaceutical Science, and Physical and Theoretical Chemistry), PubMed, and DOAJ. Its Impact Factor is 4.6, CiteScore is 5.9, SJR is 0.865, and h-index is 261.

Annual output is approximately 4,828 articles, with over 60,000 total articles across its history. The APC is CHF 2,700. Average submission-to-publication time is 38 days, with a median of 34 days. Revised manuscripts are reviewed within 3 days.

These numbers put Molecules firmly in the mid-tier of chemistry journals — not Nature Chemistry (IF 20.2) or JACS (IF 14.4), but a credible venue that most chemistry departments recognize.

A predatory journal does not maintain SCIE indexing for nearly three decades, accumulate an h-index of 261, or build a 1,700-member editorial board of working chemists. Molecules passes every standard test for journal legitimacy.

The risk is the special issue model and review speed.

In 2022, 88% of all MDPI articles appeared in special issues rather than regular issues (since reduced to 55%). Guest editors running those issues become the primary quality gatekeepers, and not all are equally rigorous. A Science investigation found that MDPI accounted for 87% of special issues where guest editors contributed more than a third of the papers themselves. Thirteen percent of MDPI special issues exceeded a threshold where more than a third of papers were co-authored by the guest editor. For Molecules specifically, the quality of any given paper depends heavily on which special issue it appeared in and who was overseeing it.

The 38-day average submission-to-publication time is roughly five times faster than traditional chemistry journals where 2-4 months for first decision and 6+ months for total publication is normal. Reviewers get 7-10 days. Whether meaningful chemistry peer review — evaluating experimental procedures, spectral data, synthetic methodology — can consistently happen in that window is the core question.

The 2018 mass resignation at MDPI's Nutrients journal, where 10 senior editors left over alleged pressure to accept mediocre manuscripts, illustrates a structural tension across MDPI between editorial selectivity and business growth. That incident did not involve Molecules directly, but it describes a publisher-wide dynamic.

The better question is whether Molecules is the right journal for this particular paper. If your chemistry research is sound, you want open-access publication with PubMed indexing, and a mid-tier IF works for your career, Molecules is a legitimate option with nearly 30 years of track record.

If your paper has enough novelty for Organic Letters, Chemical Communications, JACS, or Angewandte Chemie, those venues carry a stronger selectivity signal. If your institution uses Finland's JUFO system, publication in Molecules earns minimal credit. If you want your work associated with a society publisher (ACS, RSC, Wiley-VCH), those carry different reputational weight.

If submitting to a special issue, vet the guest editor's record and check whether they have published excessively in their own issues.

If you are considering a Molecules special issue, do some homework first. Check the guest editor's h-index and publication record — are they active researchers in the special issue's topic? Look at other papers already published in the issue and assess whether quality is consistent with what you expect from an IF 4.6 journal. Check whether the guest editor has published their own papers in the issue — one paper is common, three or four is a red flag. Compare the special issue's topic to the guest editor's expertise. A mismatch suggests the editor may have been recruited for volume rather than knowledge.

For regular issues, the journal's main editorial pipeline provides more consistent oversight.

Molecules is not predatory. It has legitimate indexing, real peer review, a large qualified editorial board, and stable impact metrics built over nearly 30 years. The concerns about MDPI's special issue model, review speed, and institutional downgrades are worth understanding, but they describe a publisher that prioritizes volume and speed — not one that fakes the publishing process.

For the full picture on MDPI as a publisher, see our MDPI predatory assessment. To evaluate whether your manuscript fits Molecules, try a free manuscript review.