Naphthalenediimides,　a　class　of　organic　dyes　with　an　expanded　pi-electron-deficient　plane,　have　attracted　considerable　interest　because　of　their　photoinduced　electron　transfer　from　neutral　organic　moieties　to　stable　anionic　radicals.　This　makes　them　excellent　candidates　for　organic　linkers　in　the　construction　of　photochromic　coordination　polymers.　Such　a　photochromic　two-dimensional　coordination　polymer　has　been　prepared　using　N,N＇-bis(pyridin-4-ylmethyl)naphthalene-1,8:4,5-bis(dicarboximide)　(DPMNI).　In　crystallization　tubes,　upon　slow　diffusion　of　an　MeOH　solution　of　cadmium　perchlorate　into　a　CHCl3　solution　of　DPMNI,　the　complex　poly[[bis[mu(2)-2,7-bis(pyridin-4-ylmethyl)benzo[imn][3,8]phenanthroline-1,3,6,8(2H,7H)-tetrone-kappa　N-2:N＇]bis(perchlorato-kappa　O)cadmium(II)]　chloroform　tetrasolvate],　{[Cd(C26H16N4O4)(2)(ClO4)(2)]center　dot-4CHCl(3)}(n),　(I),　was　obtained.　The　asymmetric　unit　contains　one　Cd2+　cation,　two　DPMNI　ligands,　two　coordinated　ClO4-　anions　and　four　CHCl3　solvent　molecules.　Each　Cd2+　cation　is　interconnected　by　four　DPMNI　linkers　to　generate　a　neutral　two-dimensional　naphthalenediimide　coordination　network　with　all　the　ClO4-　anions　above　or　below　this　plane.　Strong　interlaminar　anion-pi　interactions　between　the　coordinated　ClO4-　anions　and　the　imide　rings　of　an　adjacent　layer　lead　to　a　three-dimensional　supramolecular　structure.　Compound　(I)　exhibits　reversible　photochromic　behaviour　and　photocontrolled　tunable　luminescence　properties,　which　may　originate　from　the　photoinduced　electron-transfer　generation　of　radicals　in　the　DPMNI　ligand.