Design and synthesis of three novel [2 + 2] self-assembled molecular rectangles 1-3via coordination driven self-assembly of predesigned Pd(ii) ligands is reported. 1,8-Diethynylanthracene was assembled with trans-Pd(PEt3)2Cl2 in the presence of CuCl catalyst to yield a neutral rectangle 1via Pd-C bond formation. Complex 1 represents the first example of a neutral molecular rectangle obtained via C-Pd coordination driven self-assembly. A new Pd2II organometallic building block with 180° bite-angle 1,4-bis[trans-(ethynyl) Pd(PEt3)2(NO3)]benzene (M2) containing ethynyl functionality was synthesized in reasonable yield by employing Sonagashira coupling reaction. Self-assembly of M2 with two organic clip-type donors (L2-L3) afforded [2 + 2] self-assembled molecular rectangles 2 and 3, respectively [L2 = 1,8-bis(4-pyridylethynyl)anthracene; L3 = 1,3-bis(3-pyridyl) isophthalamide]. The macrocycles 1-3 were fully characterized by multinuclear NMR and ESI-MS spectroscopic techniques, and in case of 1 the structure was unambiguously determined by single crystal X-ray diffraction analysis. Incorporation of Pd-ethynyl bonds helped to make the assemblies π-electron rich and fluorescent in nature. Complexes 1-2 showed quenching of fluorescence intensity in solution in presence of nitroaromatics, which are the chemical signatures of many commercially available explosives. © 2011 The Royal Society of Chemistry.