The optical and self-assembly properties of HDPPBA-C, HDPPBA-N and HDPPH were followed by UV-Vis absorption at variable temperature in different solvents and concentrations, and Fourier transform infrared (FTIR) spectroscopy. The amide-containing derivatives as well as the control molecule display broad absorption bands ranging from 400 to 600 nm at 20 °C in chloroform with absorption maxima at  = 521 nm and  = 560 nm (Figure ). The three derivatives do not show any sign of aggregation in chloroform at 20 °C at 0.5 mg/ml, and the absorption bands do not change upon heating or changing the concentration (Figure ). Additional absorption bands appeared at lower energy when HDPPBA-C and HDPPBA-N were measured in different solvents, such as chlorobenzene, toluene and ethyl acetate at the same concentration (Figure and) with max at 620 nm in chlorobenzene and toluene, and at 630 nm in ethyl acetate for HDPPBA-C, and max at 617 nm in chlorobenzene, 620 in toluene and 624 nm in ethyl acetate for HDPPBA-N. Interestingly, this band at lower energy was not observed for the control molecule HDPPH, which displayed equal spectra in all the solvents (Figure ). When comparing to previously described amide-containing DPPs in our group, where the -position of the thiophene was not functionalized with hexyl tails, a bathochromic shift of 10 nm of the J-aggregate band was observed. The additional bands above 600 nm are attributed to the formation of J-type aggregates, as detected for the other families of H-bonded DPPs previously described by us and other groups. Furthermore, the differences found between the amide derivatives and the control suggest that H-bonds are involved in the formation of such types of aggregates. To confirm this hypothesis, the absorption spectra were measured after the addition of methanol, an H-bonding competing solvent, showing that the J-aggregate bands disappear (Figure ).