This Soviet Union commemorative stamp was issued in 1965 to mark the 20th IUPAC Congress held in Moscow. The design, rendered in modernist Soviet style, combines scientific motifs — molecular structures and chemical apparatus — symbolizing the USSR’s commitment to advancing global chemical research. The upper left corner features the IUPAC emblem and the inscription “XX IUPAC 1965 MOSCOW,” while the lower section shows stylized molecular diagrams. Printed in turquoise, pink, black, and white, it reflects both scientific progress and international collaboration during the Cold War era.