Preparation, crystal structures, spectroscopic and thermal analyses of two co-crystals of [M(H2O)6][M(dipic)2] and (atrH)2[M(dipic)2] (M = Zn, Ni, dipic = dipicolinate; atr = 3-amino-1H-1,2,4-triazole) with isostructural crystal systems

► Two new co-crystals were prepared. ► The complexes consist of two [M(dipic)2]2− anions with either organic and complex cations. ► There is no report in the literature of any [Zn(dipic)]2− or [Ni(dipic)]2− complexes with atrH+ as a counter ion. ► Hydrogen bonding interactions contribute to the formation of 3D structures.