We then explored the substrate scope of olefins (Scheme 3B). In general, styrene derivatives having an electron-donating group (products 11a,b) gave lower yields than with an electronwithdrawing group (11c,d), likely due to instability of the products during column chromatography. 1,1-Disubstituted or 1,2disubstituted styrene derivatives delivered 1,2-dichlorination products in high yields (11e: 93%, 11f: 71%, 11g: 80%). Despite having opposite electronic properties, both 11f and 11g can be obtained with good yields, demonstrating the generality of radical chlorination compared to classical electrophilic chlorination. The protocol was also successfully applied to non-activated olefins (products 11h-j). In the case of allyl benzene, an ipso rearrangement was observed, giving a 5:1 mixture of 11h1 and 11h2 in 71% yield. Product 11i was isolated in 79% yield starting from 4-phenyl-1-butene. Although it was reported that 6a can be used as an efficient reagent to oxidize alcohols, the reaction shows good tolerance to both alcohols and amines, yielding 74% of product 11j starting from the drug Oxprenolol. Further exploration of the substrate scope for C-H chlorination revealed excellent yields with 4-bromo ethyl benzene and ethyl benzene (products 13a and 13b) (Scheme 3C). When starting from an aryl cyclobutane, we obtained C-H functionalization instead of C-C cleavage, resulting in cyclobutyl alcohol 13c after isolation on reverse phase column chromatography. We were also able to achieve C-H chlorination of -carbonyl C-H bonds, yielding 93% of isolated product 13d, although four equivalents of 6a were necessary to complete the reaction. Starting from the substrate having both secondary benzylic and -carbonyl C-H bonds, 13e and 13f were isolated as the major products. Only a trace amount of benzylic chlorination was observed from the crude mixture. Interestingly, we obtained product 13g in 64% yield without chlorination of the acetyl group, likely due to the unfavorable formation of a primary radical on the acetyl group. The reaction favored the less steric hindered benzylic C-H bond of Ibuprofen methyl ester, resulting in 75% yield of product 13h. Lastly, the protocol was successful in case of Benzbromarone, giving 43% yield of product 13i. The simplicity of the protocol allowed us to use benzylic chlorides as intermediates for a telescoped functionalization (Scheme 4A). We focused on 1,1-diaryl motifs, which are frequently encountered in bioactive molecules (Scheme 1E). Following modified reported conditions for Friedel-Crafts arylation, we successfully performed a one-pot chlorination/arylation sequence, resulting in 1,1-diaryl-3-chloro scaffolds 15 starting from cyclopropanes 8. The nucleophilic substitution happened at room temperature in the presence of iron(III) chloride and a base, and purification of the chlorinated intermediate was not required. Cyclopropane 8a was converted to 15a in 77% yield after two steps. The reaction was successful for both bromo and boron substituted substrates (products 15b,c). However, the nucleophilic substitution is not efficient with cyclopropanes bearing electron-withdrawing groups, as exemplified by product 15d obtained in 26% only, likely due to the difficulty of forming the benzylic carbocation. Using phenol as a nucleophile exclusively delivered aromatic substitution over O-alkylation, giving a 52% yield of 15f as a para/ortho mixture in a 7:1 ratio. Products 15g and 15h were obtained in 76% and 66% yield, respectively, using 1,3-benzodioxole and benzothiophene as nucleophiles. Arylation product 15i was obtained in 45% yield starting from Indomethacin methyl ester. The drug Nimesulide and Estrone can also be used for the aromatic substitution (products 15j and 15k), demonstrating the possibility for late-stage functionalization of bioactive compounds. We also explored the same reaction conditions with sulfonamides as nucleophiles, obtaining good yields from para-methoxyphenyl sulfonamide (product 15l, 75%) and the drug Celecoxib (15m, 70%). In this case, one equivalent of iron chloride was required to accelerate the reaction. Alcohol and thiol nucleophiles can also be used under the same reaction conditions, giving products 15n-p in 65-74% yield. Additionally, C-H arylation and 1,2 chloro-arylation of styrene derivatives can be achieved, yielding 61% of product 15q and 60% of product 15r. During scope exploration, we often noticed the presence of a byproduct resulting from benzylic arylation with iodobenzene 14. This suggests the possibility of reusing 14 as a substrate in the C-C bond forming step. Since 14 has low reactivity in Friedel-Craftstype arylation, we envisaged the use of a Nickel-catalyzed reductive coupling of 14 with the benzylic chloride intermediate to give a 1,1-diaryl scaffold in an atom-economic manner (Scheme 4B). Following modified reported conditions (see SI for details on optimization), we carried out the reductive coupling directly from the concentrated crude mixture after ring-opening chlorination. After two steps, we successfully obtained chloroarylation products 16a-d with yields ranging from 49% to 61%. This approach is suitable for both electron-poor and electron-rich aromatic partners, making it complementary to the Friedel-Crafts type reaction. We expected that 1,3 chlorinated compounds could also serve as dielectrophilic intermediates (Scheme 4C). A double substitution was conducted with sodium sulfonate and sodium azide, resulting in 57% yield of disulfonate 17a and 63% yield of diazidation product 17b over two steps. Lastly, we used the same method to perform a telescoped C-H benzylic functionalization with azide and morpholine nucleophiles, producing C-H amination products 18a-c (Scheme 4D). All the reactions were conducted without purification of the chlorinated intermediates, demonstrating the practicability of our method. Scheme 4. Two-step protocol for benzylic functionalization. Scope on 0.2 mmol scale. 0.5 equiv. of FeCl3. 1.0 equiv. of FeCl3.