Ball　milling　Knoevenagel　condensation　reactions　of　dialdehyde　aromatic　derivatives　and　methylene-activated　derivatives　have　been　conducted　in　air　and　solvent-free　systems　with　ammonium　acetate　as　the　catalyst　to　obtain　a　series　of　nonfullerene　small　molecular　acceptors.　Organic　solar　cells　based　on　the　fully　non-fused　ring　acceptor　SMA-8　showed　a　power　conversion　efficiency　of　10.02%.　©　2022　The　Royal　Society　of　Chemistry.