Butatrienylidene (H₂C₄) was discovered in 1991 in the circumstellar shell of IRC + 10216 by Cernicharo et al. using the IRAM 30m radiotelescope using experimental spectra of the species measured by Killian et al. Subsequent detections include dense molecular cloud TMC-1 by Kawaguchi et al. in 1991 and toward the low-mass protostar IRAS 04368+2557 in L1527 by Sakai et al. in 2008.

The H₂C_n species are known as cumulene carbenes. For an even number of carbon atoms, they are much less stable than their acetylenic counterparts, HC_nH, in the case of of butatrienylidene, diacetylene. However, where the acetylenic compounds have no permanent dipole moments, the cumulene carbons have very large dipole moments and therefore have intense rotational spectra.