Reactions of CuSCN with tetramethylthiuram &sulfide in CH3CN in the presence of styrene and N.N.N'.N",N"-pentarnethyldiethylenetriamine gave rise to a new copper(1) complex of N,W-dimethyldithiocabamate ( [CU(S,CNM~~]~),. The title compound crystallized in the triclinic P-1 space group with lattice parameters a=0.7610(4) nrn, b=0.8911(4) nm. c=0.9268(5) nm. a=68.66(1)", p =83.88(2)", y=79.31(2)", V= 0.5748(5) nm3, Z = 2 . The compound has a unique 1D chain smcture composed of CuSCSCuSCS eight-membered rings and a pair of C U S bonds, the structure of which has been determined by singlecrystal X-ray crystallography.The isolation of this compound may provide some helpful information for the cause of the induction periods of the reverse atom transfer radical polymerization.