Two Green group papers published in Intl. J. Chem. Kinet. are among the journal's top cited papers over the past two years and are made free to access until March on Intl. J. Chem. Kinet. The perspective “Perspective on Mechanism Development and Structure‐Activity Relationships for Gas‐Phase Atmospheric Chemistry” (https://onlinelibrary.wiley.com/doi/full/10.1002/kin.21172) contributed by Mark J. Goldman and Prof. William H. Green discusses necessary future mechanism development and research efforts for the sustainable development of chemically detailed mechnisms. The article “An Extended Group Additivity Method for Polycyclic Thermochemistry Estimation” (https://onlinelibrary.wiley.com/doi/full/10.1002/kin.21158) contributed by Kehang Han, Adeel Jamal, Colin A. Grambow, Zachary J. Buras and Prof. William H. Green proposes a novel method to estimate polycyclic thermochemistry which significantly improves on group additivity methods. A corresponding web application is available at http://rmg.mit.edu/molecule_search.