K4Cu3(C3N3O3)2X (X = Cl, Br): strong anisotropic layered semiconductors containing mixed p–p and d–p conjugated π-bonds

Metal cyanurates K₄Cu₃(C₃N₃O₃)₂X (X = Cl, Br) containing π-conjugated anions are synthesized in flame-sealed silica tubes and they exhibit 2D graphene-like layered structures and intriguing semiconductor behaviors.