2,7-Poly(S-fluorenone) (PF) (1), a unique electron-deficient conjugated polymer, was prepared via a precursor route, using 2,7-poly(spiro[4',4'-dioctyl-2',6'-dioxocyclohexane-1', 9-fluorene]) (10b) (POFK) as precursor polymer. Ketalization of 2,7-dibromo-9-fluorenone (6) with the diol 2,2-dioctyl-1,3-propanediol (8b) afforded a dibrominated ketal derivative of fluorenone (9b) which after Ni(0)-induced coupling provided the well-processable, structurally defined precursor polymer 10b with a polyphenylene backbone. Conversion to PF (1) proceeded smoothly by treating a; POFK (10b) film with dichloroacetic acid. The cyclic voltammogram of PF (1) exhibits a reversible reduction with a E-1/2(0) of -1.48 V vs Fc/Fc(+) which qualifies 1, together with its facile accessibility, e.g., as electron transport material in multilayer LED.