[2] Sekanina was a close collaborator with other Czech and Slovak Communist activists and intellectuals such as Julius Fučík, Václav Kopecký, Vladimír Clementis and Jan Šverma.

[2] He was heavily involved in the staged trial of Georgi Dimitrov and his comrades, accused in 1933 of setting fire to the Reichstag.

He was originally supposed to become the defense attorney for the co-accused chairman of the parliamentary faction Ernst Torgler in the Leipzig trial, but the Reich did not allow it.

[3] In the 1930s, he was a co-founder and functionary of many left-wing and anti-fascist organizations, such as the Society for Economic and Cultural Rapprochement with the USSR, the Left Front, the Union of Friends of the USSR, the Committee for Aid to Democratic Spain, the League for Human Rights, the Šalda Committee, the Socialist Academy and the D 34 theatre.

After the outbreak of World War II, Sekanina was deported to Sachsenhausen concentration camp, where he died on 21 May 1940, possibly under torture.