The prevalent structural motif in d-HAT photocatalysts features an oxo group, endowing them with a distinctive oxygen-centered radical character in their reactive excited states for hydrogen abstraction. These photocatalysts can be classified as (i) carbonyl derivatives, including aromatic ketones, diacetyls, aldehydes, and neutral Eosin Y , and (ii) inorganic oxide derivatives, including decatungstate anion ([W10O32] 4-), uranyl cation ([UO2] 2+ ), and antimony oxo porphyrin complexes. However, each d-HAT photocatalyst has its limitations. For example, aromatic ketones could easily undergo irreversible dimerization during photoreaction, and therefore, a high photo-catalyst loading (up to a few equivalents relative to substrate) is generally required to compensate for the catalyst loss. Photoexcited [W10O32] -anion can abstract hydrogen from strong bonds, such as the C-H bond in methane (BDE = 105 kcal/mol). However, its chemistry is mainly restricted by the need for highly energetic UV light (<400 nm). Therefore, there is still strong interest in discovering new classes of visible-light-absorbing d-HAT photocatalysts that provide bond-cleaving and forming capabilities complementary to the existing ones.