2-(4'-Bromobenzoyl) benzoic acid was prepared from phthalic anhydride and bromobenzene, then 3-bromofluorenone was synthesized after passing through several steps. This was converted into 3-bromofluorene-9, 9-dichloride, dechlorination of which yielded 3, 3'-dibromobis (biphenylene) ethylene. By the Michael condensation reaction of the ethylene compound and 3-bromofl iorene, fluorene, etc., 3, 3', 3''-tribromotris (biphenylene) propane, 3, 3'-dibromotris-(biphenylene) propane, 3'-bromotris (biphenylene) propane, etc. were synthesized.Thermal decomposition of these compounds gave none of their isomers but the presences of 3, 3'-dibromobis (biphenylene) ethylene, -ethane, bis (biphenylene)-ethylene, etc. were confirmed in the thermal decomposition products.