The New Synagogue of Szeged was built between 1900-1903 in a Historicising and Art Nouveau style. With its 1340 seats and 48.5 meters tall central dome, it is the fourth largest in Europe. It was designed by architect Lipót Baumhorn, under the inspiration of and in cooperation with Dr Immánuel Löw, the chief rabbi of the Neolog Community of Szeged. Without doubt, Baumhorn’s masterpiece was the Neolog Synagogue in Szeged, which, in addition to its complex form and its large size, was made unique by the symbolic depiction of the Jewish religion. The architect and the rabbi worked in tight cooperation on the designing process of the synagogue. The holidays are visualised in ten scenes on the ground floor windows, and these are repeated in the two large, three-lobed windows of the gallery. In the inaugural speech of the synagogue, Löw also described the windows and the central concept of the building. According to recent research results, we know that Löw was very much involved in the design of the windows. Among the recently digitised materials of the Szeged Jewish Archive, we can still find the drafts for the decorative painting and the windows written in German and Hungarian languages. Löw added in handwriting the Latin names of the plants for each holiday and drew into the drafts which ritual object and inscription should be added to which window. The correspondence between the chief rabbi, the architect and the Manó Róth, the glass designer, provides insight into the process of making the world-famous stained-glass windows at the turn of the century and also proves the tight cooperation between these men. The current paper presents Löw’s involvement in the design process.