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.