The article discusses the thermochemistry of proton-coupled electron transfer (PCET) reactions, which are crucial in various chemical and biochemical processes, from biological catalysis to industrial applications. PCET involves the transfer of both protons and electrons, often in multiple steps, and can be concerted or sequential. The authors provide a comprehensive overview of the thermochemical properties of reagents involved in PCET, focusing on 1-electron and 1-proton transfers. They emphasize the importance of understanding the thermochemistry to determine whether electron and proton transfer occur together or separately. The review tabulates and analyzes the thermochemical properties of reagents, including their acidity/basicity, reduction potentials, and bond dissociation free energies (BDPEs). The authors also discuss the distinction between hydrogen atom transfer (HAT) and separated concerted proton-electron transfer (CPET), and provide detailed methods for calculating bond dissociation enthalpies (BDEs) and free energies (BDFEs). The thermochemical data are presented for various classes of compounds, such as hydroxylamines, phenols, and tyrosine, highlighting their significance in biological and industrial contexts. The article aims to encourage the use of BDFEs over BDEs to better understand the thermodynamics of PCET reactions.The article discusses the thermochemistry of proton-coupled electron transfer (PCET) reactions, which are crucial in various chemical and biochemical processes, from biological catalysis to industrial applications. PCET involves the transfer of both protons and electrons, often in multiple steps, and can be concerted or sequential. The authors provide a comprehensive overview of the thermochemical properties of reagents involved in PCET, focusing on 1-electron and 1-proton transfers. They emphasize the importance of understanding the thermochemistry to determine whether electron and proton transfer occur together or separately. The review tabulates and analyzes the thermochemical properties of reagents, including their acidity/basicity, reduction potentials, and bond dissociation free energies (BDPEs). The authors also discuss the distinction between hydrogen atom transfer (HAT) and separated concerted proton-electron transfer (CPET), and provide detailed methods for calculating bond dissociation enthalpies (BDEs) and free energies (BDFEs). The thermochemical data are presented for various classes of compounds, such as hydroxylamines, phenols, and tyrosine, highlighting their significance in biological and industrial contexts. The article aims to encourage the use of BDFEs over BDEs to better understand the thermodynamics of PCET reactions.