We studied the pressure effects on 1,3,5-trithia-2,4,6-triazapentalenyl (TTTA), which exhibits paramagnetic-diamagnetic bistability in the range between T-cdown arrow = 230 K and T-cup arrow = 305 K at ambient pressure. The bistable temperature range shifted toward high temperatures with dT(cup arrow)/dp = 20 +/- 10 KGPa(-1) and dT(cdown arrow)/dp = 45 +/- 20 KGPa(-1) at p = 0 GPa, hence the room-temperature bistability was stabilized by pressure. (C) 2004 Elsevier B.V. All rights reserved.