Methyltriacetylene (CH₃C₆H) was identified by Remijan et al. toward Taurus Molecular Cloud 1 (TMC-1), as reported in 2006. The detection was based on 10 rotational lines observed with the Green Bank telescope. No subsequent observations of methyltriacetylene have been reported to date.

Methyltriacetylene or 1,3,5-heptatriyne is the third in the series of methyl-terminated mono- and polyacetylene (or polyyne) compounds, CH₃-(C≡C)_n-H, to be discovered in space, after methylacetylene (n=1) and methyldiacetylene (n=2). Experimental spectra of methyltetraacetylene (n=4) and methylpentaacetlyene (n=5) were characterized by Travers et al., while spectra of methylhexaacetylene (n=6) and methylheptaacetylene (n=7) were measured by Chen et al.. Theoretically, rotational constants have been calculated all the way out to for n=10 by Etim and Arunan.