Cobalts trichloride was detected in 1952 by Schäfer and Krehl in the gas phase when cobalt(II) chloride  is heated in an atmosphere of chlorine .  The trichloride is formed through the equilibrium
At 918 K (below the melting point of , 999 K), the trichloride was the predominant cobalt species in the vapor, with partial pressure of 0.72 mm Hg versus 0.62 for the dichloride. However, equilibrium shifts to the left at higher temperatures. At 1073 K, the partial pressures were 7.3 and 31.3 mm Hg, respectively.
Cobalt trichloride, in amounts sufficient to study spectroscopically, was obtained by Green and others in 1983, by sputtering cobalt electrodes with chlorine atoms and trapping the resulting molecules in frozen argon at 14 K.
A report from 1969 claims that treatment of solid cobalt(III) hydroxide · with anhydrous ether saturated with  at −20 °C produces a green solution (stable at −78 °C) with the characteristic spectrum of .
In a 1932 report, the compound was claimed to arise in the electrolysis of cobalt(II) chloride in anhydrous ethanol.