Graphical abstract This paper describes the interesting substitution effect in chlorodifluoromethyl aryl ketones and sulfones as difluoromethylating agents for phenols. It was found that, while the different substitution groups on ketone reagents 1 did not show a remarkable impact on the difluoromethylation reaction, the substitution effect on the sulfone reagents 2 was much more significant. Finally, we figured out that p-chlorophenyl chlorodifluoromethyl sulfone 2d and p-nitrophenyl chlorodifluoromethyl sulfone 2h were among the most powerful difluorocarbene reagents in this category. Highlights ► Chlorodifluoromethyl aryl ketones 1 and sulfones 2 were surveyed as:CF 2 reagents. ► The substitution groups on reagents 1 and 2 showed different effect on their reactivity. ► Two of the most efficient difluorocarbene reagents in this category have been selected. ► The different substitution effects on 1 and 2 were rationalized.