A series of discrete molecular architectures was synthesized via self-assembly of two "linear" diimidazole donors [Ll = 1,4-di(1H-imidazol-1-yObenzene and L2 = dim ethyl-1,4-phenylene)bis (1H-imidazole)] independently with cis-[(tmeda)Pd(NO3)(2)] [tmeda = N,N,N',N'-tetramethylethane-1,2-diamine], cis-[(tmeda)Pt(NO3)(2)], a diplatinum(II) acceptor (bisPt), and Pd(NO3)(2). The donors Ll and L2 are isostructural with four hydrogens in the benzene ring of whereas in L2 two of such hydrogens are substituted by methyl groups. The assemblies were characterized by NMR spectroscopy and electrospray ionization mass spectrometry analyses along with single-crystal structure determination of three of them. While the self-assembly of Ll with cis-[(tmeda)Pd(NO3)(2)] solely formed a [3 + 3] self-assembled molecular triangle (1), L2 with the same acceptor predominantly resulted in the formation of a [4 + 4] molecular square (3). Such a dramatic change in the final outcome in the coordination-driven self-assembly. by simple alkyl substitution of isostructural donors is remarkable. Interestingly, self-assembly of Ll and L2 with analogous Pt(II) acceptor cis-[(tmeda)Pt(NO3)(2)] yielded mixtures of [3 + 3] triangle and [4 + 4] square, where the molecular triangles (4 and 6) were the predominant products in both the cases. The same donors in combination with a 0 degrees acceptor bisPt independently formed the expected [2 + 2] metallo-macrocydes (8 and 9). Surprisingly, the matiocyde (9) involving L2 is found to exist in more than one conformation at room temperature. Moreover, the diimidazole donors formed unprecedented Pd6L12 molecular spheres (10 and II) when they were separately treated with Pd(NO3)(2). The imidazole moieties in the ligands are found to appear in versatile orientations in the synthesized molecules due to their rotational flexibility to produce required bite angles for the particular architecture.