AbstractDibromobenzophenone diacetals (BrC6H4)2C(OR)2undergo cross‐coupling reactions with (Bu3SnC6H4)2O in the presence of palladium catalysts to give poly (diacetal ether)s whose molecular weights reflect the solubility changes of the growing polymer chains as a function of the diacetal precursors, R = Me<1/2 CH2CH2<1/2 CH2CHMe and are significantly higher than those of polymers derived from dibromobenzophenone. New di‐zinc reagents based on diacetal derivatives were synthesized and used as organometallic coupling reagents with a range of dibromoarenes, resulting in a series of previously inaccessible poly (biphenylene ketone)s and poly (biphenylene ketone sulfone)s. While poly (biphenylene ether ketone)s are insoluble, poly (biphenylene ketone)s readily dissolve in concentrated sulfuric acid. The effects of reaction parameters on the molecular weight of poly (biphenylene ketone) were determined. © 1994 John Wiley&Sons,