We show that different electrophilic molecules can be used for selective electronic structure control of single-walled carbon nanotubes (SWNT). Electrical transport properties of SWNT field-effect transistors (SWNT-FETs) treated with four electrophilic molecules revealed that these electrophilic molecules have higher selectivity toward metallic SWNTs than toward semiconducting SWNTs. One-third of the nondepletable SWNT-FETs treated with the electrophilic molecules turned into depletable devices, while devices that originally had depletable conductance showed negligible changes after treatment. AFM images showed that treatment with nitronium ions induced complete disintegration of the nanotube sidewalls.