Karl Ziegler was born in Helsa, Germany, on November 26, 1898. At age eighteen he entered the University of Marburg/Lahn to begin advanced courses in chemistry. In 1920 he received his doctorate in organic chemistry. Following a brief stint at the University of Frankfurt/Main, he became a professor at the University of Heidelberg, where he remained for 10 years. He married Maria Kurz in 1922.

Ziegler became interested in trivalent carbon compounds--carbon molecules with three functional groups. Because these compounds are free radicals with an unbonded electrons, they tend to be highly reactive. Ziegler was specifically interested in carbons with aromatic rings as substituents because they tend to be more stable. He studied the steric and electronic effects of substituents on reactions, proving through systematic studies that stable free radicals could be formed even if the ring substituents were not present, and that larger substituents led to more stable free radicals...