Alkyl radicals are carbon radicals of normal chain and branched chain alkanes, available as reaction intermediates even at late stages of synthesis. Recently, it has become possible to generate alkyl radicals under mild conditions by using a photoredox catalyst with organic chemicals (radical precursors) under visible-light irradiation. However, since many photoredox catalysts are expensive and since it is necessary to consider the redox process of the catalysts themselves, chemical transformations may become complicated. Thus, a new method was reported on the generation of alkyl radicals by direct visible-light excitation, taking into account the photophysical properties of the organic chemicals themselves.