Abstract 5, 5′-Dichloro-2, 2′-biphenyldicarboxylic acid is readily accessible by oxidation of 3, 6-dichloro-9, 10-phenanthrenequinone, which in turn has been prepared earlier starting from DDT. Various substitutions and transformations of the 5, 5′-dichloro-2, 2′- biphenyldicarboxylic acid and derivatives are reported.
