Two dinuclear centrosymmetric coordination compounds with the bis(3,5-di-tert-butylpyrazol-1-yl)acetic acid anion (L -= bdtbpza), namely, violet [Co(bdtbpza)(NO 3 )] 2 (1) and turquoise [Cu(bdtbpza)(NO 3 )] 2 (2), are reported. Around each metal(II) ion, the Lligand is κ 3 -N,N,O coordinated, and the M-O bonds are significantly longer than both M-N bonds. The coordination sphere is completed by short nitrato and M-O bonds to a ligand that is already κ 3 -N,N,O coordinated to the adjacent intra-dinuclear metal center. Therefore, each Lligand has a total coordination number of four but [a]