Thioketene (H₂CCS) was the target of two recent searches, one successful, one unsuccessful. In 2019, McGuire et al. reported a search for thioketene toward ten sources, including Sgr B2(N), Orion-KL, Barnard 1, and TMC-1, but they did not find specific rotational transitions of the compound in any of the sources. A subsequent search by Cernicharo et al. reported in 2021 identified 6 rotatational transitions of thioketene toward TMC-1 as observed with the Yebes 40m telescope. As Cernicharo et al. noted, the unsuccessful search of McGuire et al. focused on a transition (12_0,12-11_0,11) that requires a temperature of 40 K to populate rather than lower energy transitions that are excited at 7 K. (The highest energy transition detected by Cernicharo et al. was 4₀₄-3₀₃.)

Thioketene is the sulfur analog of ketene (H₂CCO), which was first detected toward TMC-1 by Matthew & Sears in 1986 and confirmed by Irvine et al. a few years later.