Due to its small atomic radius and strong electronegativity, the introduction of atomic fluorine often engenders compounds with unique physical, chemical, biological, and functional properties [
1-
7]. Among them, trifluoromethyl-substituted organic compounds have found important applications as pharmaceuticals, agrochemicals, and organic functional materials because the biological and functional activities of organic compounds can be significantly influenced by the trifluoromethyl group [
8-
11]. Therefore, a number of trifluoromethyl-containing compounds have been developed as efficient pharmaceuticals and agrochemicals over the years [
12-
15]. Swarts-type reactions are traditional methods for incorporating CF
3 groups into aromatic backbones; however, these reactions require chlorine–fluorine exchange in the presence of HF under harsh conditions, and their range of tolerated substrates is relatively narrow [
16,
17]. Such processes are not appropriate for the late-stage incorporation of a CF
3 group into aromatic structures. To overcome these shortcomings, methods that directly trifluoromethylate aromatic compounds have been developed, including the use of aryl-boronic acids, aryl-fluoroborates, and arenediazonium salts [
18-
24]. Although significant advances have been made in the trifluoromethylation field, the flexibility, eco-friendliness, atom-economy, and selectivity of trifluoromethylation chemistry requires further improvement. For example, the selective introduction of a CF
3 group into an organic molecule through C–H functionalisation has attracted immense attention in recent years [
25-
28]. Tomashenko and Grushin reviewed and analysed aromatic C–CF
3 bond-forming reactions using metals and their complexes in 2011, and provided an outlook for future studies with emphasis on practical features [
29]. Whereafter, Studer summarized recent developments in radical trifluoromethylation reactions and promoted the development of new methods for radical trifluoromethylation in 2012 [
30]. Zhang's group published a review about the application of Langlois' reagent (NaSO
2CF
3) in trifluoromethylation reactions over the period of 2011 to 2014, which promoted the development of new methods for trifluoromethylations employing this reagent [
31]. Subsequently, numerous papers have appeared reporting the use of NaSO
2CF
3 in C–H functionalisation. Therefore, it is necessary to summarize developments made from 2015 to the present regarding the application of Langlois' reagent in C–H functionalisation.