Reaction of Ph₂CO and py₂CO with Li[N(SiMe₃)₂] and ArSCl (Ar = 2-O₂NC₆H₄, 2,4-(O₂N)₂C₆H₃) yielded Ph₂CNSAr (1a and 1b respectively) and py₂CNSAr (2a and 2b respectively). Reaction of fluorenone, C₁₂H₈CO with Li[N(SiMe₃)₂] and ArSCl under similar conditions afforded C₁₂H₈CNSAr (3a and 3b respectively). Whilst reaction of fluorenone with Li[N(SiMe₃)₂] and SCl₂ in a 2:2:1 ratio afforded the sulfur-diimide, C₁₂H₈CNSNCC₁₂H₈ (4), reaction of py₂CO with Li[N(SiMe₃)₂] and SCl₂ under similar conditions afforded the thiazyl heterocycle [py₂CNS]Cl (5) via intramolecular coordination. The structures of 1a, 1b, 2a, 2b, 3a, 3b and 4 are determined by X-ray diffraction. In the case of 4, bond lengths and DFT studies reveal greater π-delocalisation than in 1–3.