Isothiocyanatooxomolybdenum(V) complexes, [MoO-(NCS)(R2dtc)2] (R=ethyl or dibenzyl; R2=piperidinyl or 4-morpholinyl) have been prepared and characterized. The i.r. spectral bands at 2020 cm-1 are assigned to v(CN) which suggest that thiocyanate coordinates through nitrogen. The bands at 930, 1500 and 960 cm-1 are attributed to v(MoO), v(CN) and v(CS), respectively, and indicate the presence of the MoO3+ moiety and a bidentate dithiocarbamate group. The e.p.r. and electronic spectral data together with magnetic moment values (1.69 B.M.) suggest the presence of one unpaired electron. The complexes are monomeric. The thermal decomposition behaviour of the complexes is reported. © 1984 Verlag Chemie GmbH.