The　study　about　the　supramolecular　interactions　in　the　organic–inorganic　hybrids　will　be　significant　for　the　design　of　new　photo/electrical　functional　materials.　In　this　work,　1,ω-bis(isoquinoline)alkane　cations　with　different　spacer　lengths　(n　=　3,　5,　6)　have　been　incorporated　with　iodobismuthates　to　construct　three　new　hybrids,　which　have　been　formula　as　[BIQPP]2[Bi4I16]　(1),　[BIQPT]2[Bi4I16]　(2)　and　[BIQHX]2[Bi4I16]　(3)　through　X-ray　single　crystal　diffraction　method　(BIQPP2+　=　1,3-bis(isoquinoline)propane,　BIQPT2+　=　1,5-bis(isoquinoline)　pentane,　BIQHX2+　=　1,6-bis(isoquinoline)hexane).　The　centrosymmetric　[Bi4I16]4−　anions　are　constructed　from　four　edge-sharing　BiI6　octahedra.　Interestingly,　with　the　elongation　of　spacer　length　on　isoquinoline　from　3,　5　to　6,　the　iodobismuthate　anions　exhibit　0-D　[Bi4I16]4−　tetramers　(n　=　3,　6　for　1　and　3)　and　pseudo　3-D　[Bi4I16]n4n−　network　(n　=　5,　for　2)　based　on　I···I　interactions.　Supramolecular　interactions　including　π–π　stacking　interactions　and　C–H···I　hydrogen　bonds　contribute　to　their　structural　extensions.　Consequently,　the　enhanced　red　emission　intensity　and　the　lower　thermochromic　temperature　can　be　observed　in　2.　The　clarification　on　the　spacer　effect　on　the　supramolecular　interactions　and　functional　properties　of　this　work　will　be　beneficial　for　the　design　of　new　functional　materials.　©　The　Author(s),　under　exclusive　licence　to　Springer　Science+Business　Media,　LLC,　part　of　Springer　Nature　2024.