Next, upon addition of 20 eq. TBACl relative to nickel, we observed a 113 nm bathochromic shift and decrease in molar absorptivity, resembling the spectrum of the Ni(II)Br2L2 complex (Fig. ). This complex was confirmed to be Ni(II)Cl2L2 by comparing the diffuse reflectance spectrum of the isolated species to the complex formed directly from NiCl2•glyme and 2 eq. OMebpy (See SI, Fig. ), with matching features and a reflectance maximum at ~630 nm. Additionally, the formation of Ni(II)Cl2L2 as a more active catalyst was further supported by an increase in conversion when NiCl2•glyme was used in place of NiBr2•glyme in the absence of additive (See SI, Section 6.5), though NiBr2•glyme with TBACl still gave the best conversion. Lastly, upon addition of TBABr to [Ni(II)L2DBU]Br2 we observed only a very minor change in the spectral features (Figure ), and the formation of a small amount of Ni(II)Br2L2 was confirmed in the normalized difference spectrum (See SI, Fig. ). To understand why Ni(II)Cl2L2 is responsible for the observed increase in reactivity, we next turned to studying the redox properties of the above species.