Herein, we report the use of 6a for the formation of various Csp 3 -Cl bonds including 1,3-, 1,2-and C-H-chlorinated products starting from cyclopropanes, alkenes and alkanes respectively (Scheme 1D). The most efficient protocol was established using a stoichiometric amount of 6a, but preliminary results for a catalytic method were also obtained. Additionally, we introduce a one-pot process to further functionalize benzylic chlorides with aryl, N, O, and S nucleophiles, providing a fast and modular approach to 1,1-diaryl compounds, important building blocks in the synthesis of various pharmacophores. Especially, 1,1diaryl-3-chloropropane compounds were reported as the precursors to synthesize a wide range of commercial drugs such as Prozapine (7a), Fenpiprane (7b), Diisopromine (7c), or Fendiline (7d), and other bioactive compounds via amination of the terminal chloride (Scheme 1E). Scheme 1. A. Natural products and drugs containing Csp We started our investigation by irradiating a mixture of phenylcyclopropane (8a) and chlorobenziodoxolone reagent 6b, which we had previously used as a chlorine radical source in the oxidative activation of cyclopropanes (Scheme 2A). After 4 hours of irradiation with three equivalents of 6b, we observed an 86% NMR yield of the 1,3-dichlorinated product 9a. However, further attempts to improve the yield by increasing the amount of 6b or prolonging the reaction time were unsuccessful. We then examined Willgerodt-type reagents 6a,c-e. Interestingly, a quantitative yield of 9a was formed after 15 minutes of irradiation, and only 1.2 equivalents of 6a were needed to achieve complete conversion. In contrast to electrophilic chlorination, the electronic structure of the aromatic ring did not affect the reactivity of 6, giving 9a quantitatively with either an electron-rich (6c) or electron-poor reagents (6d-e). Further screening of other common solid nitrogen-based chlorinating reagents 6f-h did not deliver the product, demonstrating the unique properties of the Willgerodt-type reagents under photolysis. Further screening of solvents showed that chloroform, acetonitrile, and ethyl acetate could also be used with a slight decrease in yield. The reaction was less efficient in acetone, methanol, water/acetonitrile mixtures or THF. To our delight, the same conditions could be applied for the 1,2 chlorination of vinyl naphthalene 10a and the C-H chlorination of ethyl arene 12a, delivering 76% of 11a and 86% of 13a (Scheme 2B). In the case of 10a and 12a, 1.5 equivalents of 6a were required to reach complete conversion. Performing a control experiment in the dark for the chlorination of 8a for 1 hour resulted in 27% of aromatic chlorination 9a1, 15% of 9a and 54% of recovered cyclopropane 8a. Only 7% of 11a was observed starting from 10a and no product was detected with 12a. These results demonstrated the dominance and higher efficiency of the radical pathway under irradiation. We consistently observed a large amount of iodobenzene ( ) remaining after irradiation of 6a, thereby, we envisioned that a catalytic process could be achieved by adding chlorine salt and an oxidant to re-generate 6a (Scheme 2C). Following a protocol reported by Gilmour and co-workers, we screened reactions in parallel with different oxidants, including Selectfluor, NFSI, oxone, and chlorine salts (LiCl, KCl, CsCl) under visible-light irradiation with 20 mol% iodobenzene (14) as catalyst. We observed the formation of products 9a, 11a, and 13a when using either Selectfluor or oxone as the oxidant. NFSI did not result in product formation for any of the three substrates. We found that the best conditions for C-C chlorination were using CsCl with Selectfluor as the oxidant, yielding 68% of product 9a. Oxone proved to be the best oxidant for chlorination of 10a and 12a, delivering 38% of 11a and 79% of 13a. However, several background reactions were observed and affected the reaction efficiency, such as fluorination in the case of 8a, polymerization of 10a and aromatic chlorination on 12a. Overall, the possibility of performing chlorinations directly from chloride salts under iodine(I/III) photocatalysis had been demonstrated. Nevertheless, the use of stoichiometric 6a still delivered better results without side reactions and required a shorter reaction time than the photocatalytic protocol. Given that 6a is an easily accessible reagent from iodobenzene ( ), we decided to continue to explore the substrate scope using stoichiometric amounts of 6a. Scheme 2. Reaction optimization and control experiments. NMR yield is reported using CH2Br2 as an internal standard. n.r = no reaction.