The tungsten imido guanidinate and amidinate complexes W(NR)Cl(3)[R'NC(NMe(2))NR'] and W(NR)Cl(3)[R'NC(Me)NR'] (R = Ph, (i)Pr, Cy; R' = (i)Pr, (t)Bu, TMS) were synthesized by reacting the corresponding imido complex W(NR)Cl(4)(OEt(2)) with the appropriate lithium amidinate or guanidinate. Crystallographic structure determination of W(N(i)Pr)Cl(3)[(i)PrNC(NMe(2))N(i)Pr] and W(N(i)()Pr)Cl(3)[(i)PrNC(Me)N(i)Pr] allows comparison of structural features between the guanidinate and amidinate ligand in the presence of an identical ancillary ligand set.