Reaction of (CF3S)2CHC(OC2H5)3 with CF3SCl or CF3SeCl in the presence of NaH in ether provides X(CF3S)2CC(O)OC2H5 (1a, b: X = CF3S, CF3Se). 1A reacts with NH3 to form (CF3S)2CHC(O)NH2 (2b) which is also obtained from (CF3S)2CHC(O)OC2H5 and NH3. Dehydration of the amide 2b yields (CF3S)2CHCN (3b), which reacts with NaH and then with CF3SX (X = Cl, SCF3) or with RfCl (Rf = CF3Se, C6F5S) to give Rf'(CF3S)2CCN [Rf' = CF3S (3c), CF3Se (3d), C6F5S (3e)]. 3C is also obtained from (CF3S)3CBr and AgCN. Hydrolysis of 3c with concn. H2SO4 leads almost quant. to (CF3S)3CC(O)NH2 (2c), which on treatment with COCl2 gives only 3c and not the corresponding isocyanate. If phosgene is replaced by oxalyl chloride and treated with 2c in a 1:1 molar ratio, (CF3S)3CC(O)NCO (4a) is formed. The urea deriv. (CF3S)3CC(O)NHC(O)NHC(O)C(SCF3)3 (4b) is obtained either by using a 2:1 molar ratio of 2c and [C(O)Cl]2 or from 2c and 4a. Treatment of (CF3S)2CHCO2H with NaH in ether and then with CF3SCl provides low yields of 2,4-bis[bis(trifluoromethylsulfanyl)methylene]-1,3-dithietane (5). X-ray structure analyses are performed for (CF3S)3CCN (3c) and the 1,3-dithietane 5.