In this work we have synthesized and characterized a new coordination compound [HgL(ClO4)2EtOH] (1), fabricated from a mixture of Hg(NO3)2 and NaClO4 with 1,2-diphenyl-1,2-bis((phenyl-(pyridin-2-yl)methylene)hydrazono)ethane (L). Single-crystal X-ray crystallography revealed the formation of a mononuclear heteroleptic discrete structure with one molecule [HgL(ClO4)2EtOH] in the asymmetric unit. The ligand L adopts a helical twist conformation. The Hg(II) cation is coordinated by four nitrogen atoms from L and by three oxygen atoms from two monocoordinated ClO4– anions and one ethanol molecule. The crystal structure of 1 is stabilized by the intermolecular O–H⋯O hydrogen bonds, and Cl–O⋯πPh and C–H⋯πPh interactions, yielding a supramolecular 3D framework. Moreover, the long Hg–N/O bonds have been analyzed in terms of coordination, semicoordination or spodium bonds using QTAIM and NCIplot index computational tools.