C-3 symmetric triformylsumanene was selectively synthesized from C3 symmetric syn-tris(oxonorborneno)benzene, featuring ring-opening/closing metathesis reactions of syn-tris(methoxymethylnorbornadieno)benzene and DDQ oxidation. Triformylsumanene can be an intermediate to synthesize C3 symmetric trisubstituted sumanenes by further transformation. Tris(ethoxycarbonylethenyl)sumanene was prepared through the Horner-Wadsworth-Emmons reaction. Its optical and electrochemical behaviors were investigated.