The initial discovery of cyanoacetylene allene (CH₂CCHC₃N) toward TMC-1 was reported in 2021 by Shingledecker and co-workers, based on observations with the 100m Green Bank Telescope as part of the GOTHAM survey. The detection was confirmed in 2022 by Fuentetaja and co-workers, supported by oberservations with the 40m Yebes Telescope as part of the QUIJOTE survey.

Both detections were based on rotational constants for cyanoacetylene allene (or hexa-4,5-diene-2-ynenitrile) measured by McCarthy and co-workers.

In addition to cyanoacetylene allene, two other allenyl compounds have been detected to date, cyanoallene and allenyl diacetylene. The parent compound propadiene (allene) doesn't have a dipole moment and is thus cannot be detected via rotational transitions. Cyanoacetylene allene is also a member of the huge group of detected CN-containing compounds.