1934 until 1940

Devoted to Organic Chemistry, Dr. Chaim Weizmann’s field of research, the Daniel Sieff Research Institute building continues to serve its original purpose as the home of the Department of Organic Chemistry. It contains Weizmann’s own lab, refurbished as a small museum for visitors, thanks to a gift of M.D. Moross.

The name of the building appears in three languages – English, Hebrew, and Arabic – testifying to Dr. Weizmann’s faith in peaceful and fruitful collaboration between Arabs and Jews in this country. To the right of the entrance, stands a tall Washingtonia palm tree, planted by his wife, pediatrician Dr. Vera Weizmann, in 1934.

The building was designed by Benjamin Chaikin, and refurbished in the 1990s with the help of the Sieff family and British friends. Portraits of members of the Sieff family are on display in the lobby.

This may be the first public building in Israel to bear the name of a philanthropic family. It was a gift of Israel Moses Sieff (1889-1972) and his wife Rebecca Sieff (1890-1966) of the UK, made to memorialize their son Daniel, at the suggestion of Dr. Chaim Weizmann.

Educated at Manchester Grammar School and Manchester University, Israel Sieff joined his boyhood friend Simon Marks in 1916 as company director, and eventually became chairman of Marks & Spencer (1964 to 1967). In 1966, he was created a life peer as Baron Sieff of Brimpton.

Sieff had supported Zionism since meeting Chaim Weizmann in 1913. Together with Weizmann, Simon Marks (son of Michael Marks, co-founder of British retailer Marks & Spencer) and Sieff helped set in motion the train of events that culminated in the Balfour Declaration of 1917. The following year, when the Zionist Commission headed by Weizmann went to Palestine to prepare the ground for the implementation of the Declaration, Sieff acted as its secretary. He then served as Weizmann’s secretary at the Versailles Conference. Sieff’s wife (and Simon Marks’ sister), Rebecca, helped found WIZO, the Women’s Zionist Organization, in 1920, and ran it for 20 years together with Vera Weizmann.

His younger son Marcus Joseph Sieff (1913–2001), joined the family firm in 1945, became a director in 1954, and, after 1967, managing director and chairman. Marcus Sieff was knighted in 1971, and received a life peerage in 1980 as Baron Sieff of Brimpton, his late father's title.

Like other members of his family he was a notable contributor to Jewish and Zionist causes. He served on the Institute’s Board of Governors for many years, acting as its Chairman (1976-1985), and later (1985-2001) as the Institute’s Chancellor.

Sir David Sieff, son of Marcus Sieff, has served the Weizmann Institute in leadership positions at the head of its friends' organization, Weizmann UK, and continues to be a most active member on the Institute’s International Board and its committees (since 1978). His sisters, the Hon. Amanda Sieff, and the Hon. Dr. Daniela Sieff, are also supporters of the Institute.

All three generations of Sieffs, as well as Rebecca Sieff, were honored by the Institute with honorary degrees.