A new N2S2Ni complex based on the 1,4-diazacycloheptane (dach) framework allows the study of the effects of ring size, in fused diamines, on the structural and chemical properties of nickel(II) dithiolate and dithioether complexes. Compared to its 1,5-diazacyclooctane (daco) derivatives, the dithiolate complex (bmedach)Ni and the S-templated, macrocyclic dithioether complex (propyl-bmedach)NiBr2 show decreased cavity sizes with narrower