From trigon 67 onwards, central exhibition themes were formulated that dealt with current issues in contemporary art. The trigon 67 exhibition itself was entitled ‘ambiente’, dealt with controversial questions about contemporary architecture and triggered a wave of indignation among visitors that lasted several weeks, with angry letters to the editor demanding Hanns Koren's resignation as head of cultural affairs and the dismissal of Wilfried Skreiner. trigon 73 (‘audiovisual messages’) was a pioneering exploration of the new medium of video and presented contributions by Bruce Nauman, Robert Morris and Richard Serra, among others
The trigon biennials were organised until 1995. Over the years, the circle of represented countries was expanded to include Hungary and, later, Germany, France, Great Britain, Spain and the Czech Republic. From 1966 onwards, trigon solo exhibitions were also organised, showcasing important artists from the participating countries.