Introduction of competing interactions in the design of asupramolecular polymer (SP) creates pathway complexity. Ester-bis-ureas contain both as trong bis-urea sticker that is responsible for the build-up of long rod-like objects by hydrogen bonding and ester groups that can interfere with this main pattern in as ubtle way. Spectroscopic (FTIR and CD), calorimetric (DSC), and scattering (SANS) techniques show that such ester-bis-ureas self-assemble into three competing rod-like SPs.T he previously unreported low-temperature SP is stabilized by hydrogen bonds between the interfering ester groups and the urea moieties.I ta lso features aw eak macroscopic alignment of the rods.T he other structures form isotropic dispersions of rods stabilized by the more classical urea-urea hydrogen bonding pattern. The transition from the low-temperature structure to the next occurs reversibly by heating and is accompanied by an increase in viscosity,arare feature for solutions in hydrocarbons.SPs are chain-like assemblies of self-complementary monomers with unique properties and applications. [1][2][3][4] Ther eversible but directional non-covalent interactions responsible for their self-assembly provides tunability and responsiveness [5] to various stimuli. This has contributed to the development of innovative catalysts, [6,7] fluorescent systems, [8,9] self-healing materials, [10,11] and gels, [12,13] among other potential applications.O ne fascinating consequence of the dynamic character of supramolecular assemblies is the capability of molecular building blocks to assemble into distinct thermodynamically or kinetically stable nanostructures. [14] An umber of studies describe the possibility of selecting one of these nanostructures by carefully controlling the conditions of aggregation, namely,t ime, [15][16][17][18] concentration, [19] temperature, [20] solvent, [21][22][23][24][25] and diffusion, [26] or by tuning the nature of the monomer. [27][28][29] This pathway complexity in the aggregation ability of the monomers is usually revealed by spectroscopic techniques that identify the structural differences in the assemblies at the nano or mesoscale (for example,kinetics of aggregation, helicity,s tacking mode,c onformation). [30,31] However,achange in the properties of the supramolecular assemblies at the macroscale has been reported for very few cases. [20,32] In fact, the properties of SPs can be considerably diversified when they form in competition with other assemblies.I ndeed, pathway complexity can be responsible for unusual behaviors such as aself-assembly that is triggered by dilution, [19] or by both increasing or decreasing the temperature. [33] In particular,w hen two competing SPs can assemble from the same monomer, [25] the transition between the two structures can result in noticeable macroscopic property changes. [20] Thei ntroduction of competing interactions in the design of as upramolecular assembly is al ogical approach to create pathway complexity.I np ractice,t his can be done through solvents [21,34,35...