Emanuel "Manny" Hirsch Bloch (May 12, 1901 – January 30, 1954)  served as the defense attorney for Julius and Ethel Rosenberg. Following their execution, he delivered the eulogy at their funeral and served as guardian for the Rosenberg's children, Michael and Robert, until they were adopted.

Source: https://en.wikipedia.org/wiki/Emanuel_Hirsch_Bloch

Renowned artist (and communist), Pablo Picasso created a double portrait of the Rosenbergs. As with Léger’s scarves, it was intended to be sold to raise defense funds for the couple and Picasso gave a dedicated copy to the the two Rosenberg boys.

Source: https://espionart.com/2018/06/19/art-in-defence-of-the-rosenbergs/

Musician Paul Robeson rallied and performed for the Rosenbergs
(Source: Robeson, Paul, 1898-1976. Letter from Paul Robeson to W. E. B. Du Bois, January 1953. W. E. B. Du Bois Papers (MS 312). Special Collections and University Archives, University of Massachusetts Amherst Libraries; http://credo.library.umass.edu/view/full/mums312-b161-i267)

"French Cubist, Fernand Léger – a member of the Communist Party – designed a bold double portrait of the couple in his distinctive colourful style. The couple’s faces are shown overlapping, Ethel in frontal view and Julius in profile, alongside a peace dove – at the time also a common symbol of Communism. Two hands are shown with fingers entwined, a bracelet on one possibly a reference to a press photograph of the couple embracing in handcuffs during their trial. The images are framed by the words ‘Liberté, Paix, Solidarité’ (‘Liberty, Peace, Solidarity’).

Lobbied President Eisenhower for Clemency (source: https://www.biography.com/news/julius-ethel-rosenberg-espionage-trial-d…)

Lobbied Eisenhower for clemency (source https://www.biography.com/news/julius-ethel-rosenberg-espionage-trial-d…)