This paper describes the synthesis and characterization of a new series of copolymers with a predominantly poly(ethylene oxide) (PEO) backbone and phenyl and/or 4,4'-biphenyl structural units. Three copolymers, poly[oxyethylene]/poly[oxyphenylene] copolymer (1), poly[oxyethylene]/poly[oxybiphenylene] copolymer (2), and poly[oxyethylene]/poly[oxyphenylene]/poly[oxybiphenylene] copolymer (3), were prepared based on modifications of hydroquinone and/or 4,4'-biphenol copolymerized with dimesylates of various length poly(ethylene glycol)s (PEGs). Depending on their composition and chain length of PEGs used in the polymerization, the copolymers show liquid crystallinity or non-liquid crystallinity.