During the Axis Occupation of Greece, he co-founded a small leftist party, the Union of People's Democracy (ELD). He served as its general secretary, while the distinguished law professor Alexandros Svolos served as its president. In 1941, ELD joined the National Liberation Front (EAM), and Tsirimokos gained a seat in EAM's central committee.
Under the Axis Occupation of Greece, he co-founded a small left-wing organization, the Union of People's Democracy (ELD). He served as its chief organizer, while the distinguished law professor Alexandros Svolos led the group. In 1941, ELD joined the National Liberation Front (EAM), and Tsirimokos was elected to EAM's central committee.