Synthesis of diaryl diselenides was restricted into only few Cu-catalyzed C-Se Cross coupling protocol where use of ligands, high reaction temp, long reaction time were required. To achieve a sustainable protocol for the synthesis of diaryl diselenides Method: Reaction of aryl diazonium fluoroborate with KSeCN was successfully performed under ball milling in absence of any ransition metal catalyst, ligands, base and external heating to get diaryl diselenides. A library of diaryl diselenides were obtained in good yields with different functional groups. First transition metal free protocol for the synthesis of diaryl diselenides has been developed successfully.