Boris Evgenievich Kochno or Kokhno (Russian: ????´? ????´?????? ?????´; 3 January 1904 – 8 December 1990) was a Russian poet, dancer and librettist.
Kochno was born in Moscow, Russia, on 3 January 1904.
His father served as a colonel in the hussars.
He studied at the Imperial Lycee in Moscow before emigrating to Paris in 1920.He was close with Karol Szymanowski, who gave him as a gift a Russian translation of the chapter The Symposium from his unpublished novel Efebos.
Szymanowski also dedicated four poems to him.
In 1920 he became Sergei Diaghilev's secretary, librettist, and eventually main collaborator.
They were also briefly lovers.
Kochno wrote the libretto of Stravinsky's Mavra (1921), George Auric's Les Fâcheux (1924), Henri Sauguet's La Chatte (1927), and of Sergei Prokofiev's ballet score The Prodigal Son (1929).
In 1925, he had an affair with Cole Porter, with whom he carried on a lengthy correspondence.
Upon Diaghilev's death, Kochno and Serge Lifar tried but failed to hold the Ballets Russes together.
The two inherited part of Diaghilev's archives and collections, which Kochno completed and part of which was acquired by the Bibliothèque nationale de France.