Gel formation by low molecular mass gelators was investigated. The gelator was trans(RR)- or trans(SS)-N, N'-n-bromoalkanoyl-1,2-diaminocyclohexane (denoted as RR-CnBr or SS-CnBr, respectively; n = the number of carbon atoms in an alkanoyl group). When n was varied from 5 to 12, the gelators formed transparent or opaque or turbid gels in benzene except for n = 8. Focusing on the end effects, the gelation behavior of CnBr was compared with that of non-brominated counterparts (denoted as RR- or SS-Cn). From the vibrational circular dichroism (VCD) spectra of enantiomeric gelator/benzene-d(6) gels, the signs of the coupled peaks around 1640 cm(-1), which were assigned to the symmetric and asymmetric C=O stretching vibrations from the higher to lower wavenumber, respectively, were opposite between SS-CnBr and SS-Cn (or between RR-CnBr and RR-Cn). On the other hand, the signs of the coupled peaks around 1550 cm(-1) assigned to the NH stretching vibrations remained unaffected. The observed reversal of the signs in the C=O couplet was rationalized in terms of the different modes of stacking in fibrils. In the case of Cn, for example, the molecules were stacked through anti-parallel double intermolecular hydrogen bonds using two pairs of >NH and >C=O groups, while, in the case of CnBr, a single intermolecular hydrogen bond was formed with the remaining pair of >NH and >C=O groups forming an intramolecular hydrogen bond. Single crystal X-ray analyses were performed for SS-C6Br and SS-C8Br. The results demonstrated that the length of the bromoalkanoyl chains drastically affected the packing modes in crystalline states.