A new strategy is proposed to prepare graphdiyne via the self-coupling reaction of hexakis(bromoethynyl)benzene (hBEP) with alkynyl bromide groups. Prominently, the reaction can proceed moderately in 12 h at room temperature. The as-synthesized film displays a porous structure, excellent chemical characteristics, and an admirable catalytic performance for the hydrogen/oxygen evolution reaction (HER/OER).