Johann Friedrich Wilhelm Adolf von Baeyer (October 31, 1835 - August 20, 1917) was a German chemist who synthesized indigo, and was the 1905 recipient of the Nobel Prize in Chemistry.

There he worked primarily in August Kekulé's laboratory, earning his doctorate (from Berlin) in 1858.
He became a lecturer at the Berlin Trade Academy in 1860, and a Professor at the University of Strasbourg in 1871.
He was the first to propose the correct formula for indole in 1869, after publishing the first synthesis three years earlier.
In 1871 he discovered the synthesis of phenolphthalein by condensation of phthalic anhydride with two equivalents of phenol under acidic conditions .
In 1872 he experimented with phenol and formaldehyde, almost preempting Leo Baekeland's later discovery of Bakelite.
In 1875 he succeeded Justus von Liebig as Chemistry Professor at the University of Munich.
In 1881 the Royal Society of London awarded Baeyer the Davy Medal for his work with indigo.
In 1905 he was awarded the Nobel Prize in Chemistry "in recognition of his services in the advancement of organic chemistry and the chemical industry, through his work on organic dyes and hydroaromatic compounds".