Baeyer, Adolf von (1835-1917), a German chemist, won the 1905 Nobel Prize in chemistry for his work on organic chemical structure and his contributions to the synthetic dye industry.

Baeyer was the oldest of five children. His father, Johann Jacob Baeyer, a lieutenant general in the Prussian army, participated in a number of scientific programs aimed at measuring and investigating the shape of the earth, in which he collaborated with the government and directed by the astronomer Friedrich Wilhelm Bessel. Johann later became head of the Berlin Geodetic Institute. Baeyer's mother, a Jew who had converted to evangelical Christianity, was the daughter of a criminal judge and the niece of an art historian.

As a pupil at the Friedrich-Wilhelms Gymnasium and at the University of Berlin, Baeyer concentrated on mathematics and physics. After completing a year of military service, in 1856, he transferred to the University of Heidelberg to study chemistry under Robert Wilhelm Bunsen. Two years later, he joined the private laboratory of German chemist Friedrich August Kekulé von Stradonitz, where he received instruction in organic chemistry. In 1858, Baeyer earned a doctorate from the University of Berlin for his studies of arsenic methyl chloride. He followed Kekulé to the University of Ghent, where he remained for a while, and then taught at the technical institute and the military academy in Berlin. In 1872, he became a professor of chemistry at the newly created University of Strasbourg, and in 1875, became professor at the University of Munich. There he established an important chemical laboratory where many young chemists who achieved fame did their training.

In the early 1860's, Baeyer began research into uric acid, which led to his discovery of barbituric acid. Barbiturates became a major class of drugs used to promote calmness and sleep. Baeyer then began research in dyes. In 1880, he devised a method for the synthesis of the dye indigo. The following year, the Royal Society of London awarded Baeyer the Davy medal for his work with indigo, which was accurate except for the stereochemical arrangement of the double bond, which was later modified. In 1883, he also determined the structure of indigo.

Baeyer is also known for his theory that helped explain why carbon rings of five or six atoms are much more common and stable than carbon rings with fewer or more atoms. This investigation of complex ring structures paved the way for later work in biochemistry.

Baeyer's other significant work includes the 1871 discovery of phenolphthalein (used as an indicator of alkalinity or acidity) and fluorescein (a powder used in dyes), and his subsequent discovery of the resin that results from the reaction between phenol and formaldehyde (which Leo Hendrik Baekeland later developed into Bakelite), and the first synthesis of a terpene in 1888.

In addition to being awarded the 1905 Nobel Prize in chemistry, that year, Baeyer was honored on his 70th birthday with a publication of his scientific papers.