Oxamidato-bridged Re(I)-based supramolecular rectangles with an ester functionality have been synthesized via an orthogonal bonding approach under solvothermal conditions. Self-assembly of Re2(CO)10 and oxamide ligands (H2L1 = N,N′-dibutyloxamide, H2L2 = N,N′-dioctyloxamide, H2L3 = N,N′-didodecyloxamide, and H2L4 = N,N′-dibenzyloxamide) with the pyridyl ligand phenyl-1,4-bis(isonicotinate) (pbin) has resulted in the formation of metallarectangles of general formula [{(CO)3Re(μ- η4-L)Re(CO)3}2(μ-pbin)2] (1-4), wherein L = N,N′-dibutyloxamidato (1), N,N′-dioctyloxamidato (2), N,N′-didodecyloxamidato (3), N,N′-dibenzyloxamidato (4) and pbin = phenyl-1,4-bis(isonicotinate). The metallarectangles have been characterized using spectroscopic techniques, and single-crystal X-ray structures have been obtained for 1 and 4. The guest binding ability of 2 has been investigated with a few aromatic amines and an amino ketone using electronic absorption and fluorescence emission spectroscopy, and the results revealed a strong binding interaction between host-guest species. The luminescence properties of 2 and 3 have been tuned using organic-aqueous solvent mixtures. © 2014 American Chemical Society.