Layered and self-penetrated cadmium isophthalate and 5-methylisophthalate coordination polymers containing bis(4-pyridylformyl)piperazine or bis(4-pyridylmethyl)homopiperazine ligands

► Luminescent cadmium coordination polymers with isophthalate (ip) or 5-methylisophthalate (mip). ► Rare T4(0)A(1) classification water tapes between [Cd2(ip)2(H2O)2(4-bpfp)]n layers. ► 2D + 2D → 3D mutual inclined interpenetration of [Cd(mip)(H2O)(4-bpfp)]n layers. ► Tetrameric cluster units linked into self-penetrated tetranodal net in [Cd4(ip)4(4-bpmh)2]n. ► Ligand-based luminescent behavior.