This paper describes the synthesis and characterization of a high molecular weight cross-conjugated polyketone synthesized via scalable Friedel Crafts chemistry. Cross-conjugated polyketones are precursors to conjugated polyions; they become orders of magnitude more conductive after a two-electron reduction and demonstrate reversible spinless doping upon protonation with acids. Cross-conjugated polyketones are a new polymer platform that possess the same optoelectronic tunability as conventional polymers but with excellent thermal and oxidative stability. We constructed a proof-of-concept organic light-emitting diode device and demonstrate that a cross-conjugated polyketone can be successfully used as an n-dopable semiconducting material.