Two new ligands N,N,N′,N′-tetraisopropyl/tetraisobutyl-3,4-pyridinedicarboxamide L1-L2 and six of their Hg(II)X 2 complexes (where X= Cl -, Br -and I -) have been synthesized and characterized. Single crystal X-ray structures of three complexes of L1 (1-3) with HgCl 2 /Br 2 / I 2 and two complexes of L2 (4-5) with HgCl 2 /Br 2 , show that these are 2D coordination polymers, with three different (one new) topologies and five coordinated Hg(II) ions, in square pyramidal coordination. Complex 6, of L2 with HgI 2 , is a dimer with a four coordinated tetrahedral Hg(II) ion. The ligands behave as 2-or 3-connecting linkers for forming CPs but only 1-connector in the dimer. Various types of H-bonding and other noncovalent interactions have been calculated, analyzed and discussed for all the complexes and the ligand L1. Though large size and soft character of iodide coupled with the steric effects of large isobutyl groups, are mainly responsible for a change in the primary structure of 6, but a significant role of the semilocalized LP···π and C-H···O non-covalent interactions into this has also been found. The latter transform this dimer to a stable 2D H-bonded network instead of a coordination polymer. The unique halide bridged 2D structure of 1 forms 1D zig-zag chains of metal ions owing to the mercurophilic interactions. Weaker interactions of the same kind further extend along the basic skeleton of 2D CP and are facilitated by LP···π, strong C-H···Cl and C-H···N(py) interactions.