Cross dehydrogenative coupling reactions (CDCs) are considerably more step‐ and atom efficient compared to classical cross coupling methods. In this context, the photochemical CDCs of hydrochlorocarbons and hydrofluorocarbons with methylarenes are herein described. This unprecedented CDC reaction concept enables a new retrosynthetic cut for the selective construction of valuable chlorinated and fluorinated organic skeletons, from industrially important dichloromethane, dichloroethane, difluoromethane (HFC‐32), and 1,1,1,2‐tetrafluoroethane (HFC‐134a). Couple up: The unprecedented cross dehydrogenative coupling (CDC) reaction of industrially important dichloromethane, 1,2‐dichloroethane, difluoromethane and 1,1,1,2‐tetrafluoroethane enables a new retrosynthetic cut for the selective construction of chlorinated and fluorinated organic skeletons.