“…16 The critical role of the pressure has been evidenced as well in the case of neutral [Ni(dithiolene)2] complexes without TTF units on the ligand backbone, in particular in the case of [Ni(dmit)2] (dmit = 1,3-dithiole-2-thione-4,5-dithiolate) which became metallic above 15.9 GPa, 17 or triclinic [Ni(Et-thiazdt)2] (Et-thiazdt = N-ethyl-1,3-thiazoline-2-thione-4,5-dithiolate) which reached a quasi-metallic state at 6.9 GPa. 18 However, other neutral [Ni(dithiolene)2] complexes, such as [Ni(dddt)2] (dddt = 5,6-dihydro-1,4-dithiin-2,3-dithiolate) 19 (Scheme 1) or monoclinic [Ni(Etthiazdt)2], 20 remained semiconducting under pressure although their conductivity dramatically increased. The case of the former is particularly intriguing since, although it is isostructural with its [Pd(dddt)2] analogue which shows characteristics of Dirac-cone material at high pressure, such as temperature-independent resistivity at 12.6 GPa and emergence of a nodal line semimetal in the band structure under pressure, 21 , 22 , 23 it remains semiconductor up to the highest applied pressure.…”