Salomon Kohn, often referred to as the “inventor of the art postcard”, was married to Gittel Kohn, née Rappaport, and had two children with her: Minna, later married Pixner (1919–2003), and Walter (1923–2016). In 1898, together with his brothers Adolf (1870–1916) and Alfred (1880–1942), he founded the postcard publishing house Brüder Kohn, with its main branch at Teinfaltstrasse 3in Vienna’s 1st district—a pioneering company that produced picture postcards designed by artists in Vienna. The company quickly became known for its groundbreaking art postcards, which combined photographic techniques with artistic design. It specialised in Vienna landmarks, caricatures, portraits of celebrities, modern developments, as well as humorous and whimsical motifs. At the beginning of the 20th century, the company expanded with several branches in Vienna and one at Friedrichstrasse 164 in Berlin. The postcard publishing house Brüder Kohn made reproductions of watercolours and oil paintings accessible to a broad public at affordable prices. All art postcards bore the imprint “B.K.W.I – Brüder Kohn Wien I”. Kohn’s cultural role, however, extended far beyond his business: His home developed into a salon for artists, writers and musicians, hosting figures such as the composer Gustav Mahler, the writer Peter Altenberg, the soprano Lotte Lehmann, the conductor Bruno Walter and the theater director Max Reinhardt. After Adolf Kohn’s death in the First World War, Salomon Kohn continued to run the business together with his brother Alfred until the “Anschluss” in March 1938.

With the Nazi takeover, the postcard publishing house was seizure; the headquarters on Teinfaltstrasse was liquidated by Otto Faltis, and the branch on Mariahilfer Strasse was Aryanized by Paul Havlu, a party member and former employee of the Herzmansky department store. Salomon Kohn was forced to work for a short time as an employee in his own company before being entirely pushed out. The expropriation extended to his private property as well: His collections of original artworks, rare postcards, photographic equipment and household items were stolen. Otto Faltis, who also profited from Salomon Kohn’s private assets, sold many works abroad or through the Viennese auction house Dorotheum. While Salomon and his wife Gittel, destitute and disenfranchised, could no longer escape the murderous machinery of National Socialism, their children managed to flee: Minna escaped to England in 1938, and Walter was rescued through a Kindertransport (Children's Transport) in 1939. Walter Kohn received the Nobel Prize in Chemistry in 1998. Salomon and Gittel Kohn were deported with transport no. 28 from Vienna to Theresienstadt on 20 June 1942, and two years later, on 28 October 1944, to Auschwitz, where they were murdered shortly after their arrival.

In four sessions in June 2004, March 2006, September 2007 and November 2010, the Art Restitution Advisory Board recommended the return of a total of 1,909 objects from the National Library and the Theater Museum to the legal successors of Salomon Kohn. Numerous other objects from his collection are considered missing today.