A convenient and effective protocol for the ruthenium‐catalyzed C–H selenylations of benzamide was achieved under mild reaction conditions. The robust ruthenium catalyst tolerated a wide range of functional groups and set the stage for the preparation for diversely decorated benzamides. The amide directing group could be transferred to carboxylic acid, aldehyde and tetrazoles. Preliminary mechanistic study indicated a base‐assisted electrophilic‐type substitution C–H activation event. The easily transformable amide directing groups assisted ortho‐C–H selenylations of arenes with 1,2‐diphenyldiselane by robust ruthenium catalyst were achieved with ample scope under mild reaction conditions. This general approach offered a straightforward access to various functional group substituted diarylselenide containing compounds. The plausible mechanism was proposed after the detailed mechanistic studies.