TlCsH, displays absorption maxima at 228 and 280 nm which are assigned to metal-centred sp and ligand-to-metal charge transfer (LMCT) transitions, respectively. The complex shows an emission at A,, = 360 nm which originates from a low-energy sp excited state. The photolysis of TIC,H, in methanol proceeds according to the equation TICsH, + CH,OH + TIOH + H, + C,H, (pentafulvene) with 4 = 0.1 at hirr = 254 nm and O.M)8 at 313 nm. It is suggested that this photoreaction is induced by LMCT excitation.