An exciting development in the 1970's involved the discovery of cyanopolyacetylenes in the interstellar medium by means of the radio telescope of the Algonquin Radio Observatory (ARO) near Lake Traverse in Algonquin Park, Ontario. The work resulted from a collaboration among a small group, including microwave spectroscopists Harry Kroto and Takeshi Oka, along with radio astronomers Lorne Avery, Norman Broten, and John MacLeod.

The microwave spectrum of cyanodiacetylene, H(C=C)2 CN, was first measured in the laboratory and subsequently found in the interstellar medium. The next step involved the preparation of cyanotriacetylene and measurement of its microwave spectrum. This molecule was also detected in the interstellar medium. Larger molecules in this series are difficult to prepare in the laboratory on account of their tendency to explode, although their microwave spectrum can be predicted with reasonable certainty.

Indeed, cyanotetra-acetylene and cyanopenta-acetylene have subsequently been found and their assignments checked, since the frequencies observed form nearly regular series with spacings characteristic of the individual molecule. All the molecules are linear, and are the longest molecules found in the interstellar medium.