The treatment of diphenylthallium(III) compounds TIPh(2)X [X = Br, OH or S2P(C6H11)(2)] with dicyclohexyldithiophosphinic acid, HS(S)P(C6H11)(2), led to 'protodemetallation' i.e. loss of one or more phenyl groups from thallium, with formation of benzene formation of [TiPh{S2P(C6H11)(2)}(2)] and [Tl{S2P(C6H11)(2)}(3)]. CHCl3. The crystal structures of these compounds and that of [TlPh(2){P-2(C6H11)(2)}(2)] were solved by X-ray diffraction, which indicated that they all crystallize in the triclinic space group P (1) over bar with Z = 2. For [TlPh(2){S2P(C6H11)(2)}] a = 10.141(1), b = 10.315(2) and c = 11.913(2) Angstrom, alpha = 94.46(1), beta = 101.45(1) and gamma = 91.01(1)degrees; the thallium atom is co-ordinated to one carbon atom of each phenyl and to both sulfur atoms of a dicyclohexyldithiophosphinate ligand [S2P(C6H11)(2)], and weakly interacts with two neighbouring ligands. For [TlPh{S2P(C6H11)(2)}(2)] a = 9.442(1), b = 10.809(2) and c = 18.256(2) Angstrom, alpha = 80.41(1), beta = 86.95(1) and gamma = 72.52(1)degrees; the thallium atom is co-ordinated to a phenyl carbon atom and to both sulfur atoms of each anisobidentate S2P(C6H11)(2) ligand. For [Tl{S2P(C6H11)(2)}(3)] (which incorporates a chloroform solvent molecule) a = 15.539(1), b = 16.23(3) and c = 10.556(1) Angstrom, alpha = 103.13(1), beta = 91.71(1) and gamma = 111.56(2)degrees; the thallium atom is co-ordinated to three pairs of sulfur atoms from two very anisobidentate ligands and one practically isobidentate dithiophosphinate. The IR, Raman, and H-1, C-13, P-31 and Tl-205 NMR spectra of the compounds have also been recorded and analysed.