Jan Zwartendijk was the head of the Philips branch office in Lithuania. Shortly after the Soviet occupation of Lithuania in June 1940, the Dutch government in exile also appointed him honorary consul in Kaunas.
Numerous Jewish refugees were living in Lithuania at this time, most of them having fled Poland when the Germans occupied the country. As honorary consul, Zwartendijk awarded entry permits for the island of Curaçao and other Dutch colonies in the Caribbean to Jewish refugees. They hoped the permits would help them evade Soviet repression. Zwartendijk issued over 1,000 of these papers within nine days. Though the persecuted Jews could not use the documents to travel directly to their destination, they could take them to the Japanese consulate in Kaunas. The Japanese consul Chiune Sugihara then issued them the necessary transit visas for Japan. The Philips branch was seized by the Soviet Union in early March 1940, and Zwartendijk had to leave Kaunas due to the uncertain situation. He returned to the Netherlands shortly after.
Zwartendijk was honored as Righteous Among the Nations in 1997.