In recent years many attempts have been made to prepare easily handled and soluble polyphenylene polymers. The polyphenylenes are theoretically of interest for aerospace applications, as they are thermally and oxidatively stable, and are resistant to most corrosive environments. Unfortunately, the completely para-oriented polyphenylenes are characterized by extreme infusibility and intractability; and even mixed m-and p-polyphenylenes are soluble only with considerable difficulty. s 2