Two mononuclear zinc(II) complexes of newly designed carboxamide derivatives, formulated as [Zn(L¹)₃](ClO₄)₂ (1) and [Zn(L²)₃](ClO₄)₂ (2) [where L¹ = 𝑁-(furan-2-ylmethyl)-2-pyridinecarboxamide and L² = 𝑁-(thiophen-2-ylmethyl)-2-pyridine-carboxamide], have been isolated in pure form in the reaction of perchlorate salts of Zn(II) with ligands L¹ and L², respectively. The two complexes were characterized by physicochemical and spectroscopic tools, and by X-ray crystal structures of both ligands and the complex 1. In complex 1, zinc(II) is chelated by three ligands with a distorted octahedral geometry. The DNA-binding properties of zinc complexes 1 and 2 have been investigated by spectroscopic methods and viscosity measurements. The results suggest that both complexes 1 and 2 bind to DNA in an intercalation mode between the uncoordinated furan or thiophene chromophore and the base pairs of DNA.