J-aggregates are formed for 3,3'-disulfopropyl-5,5'-dichlorothiacyanine (Tc) and 3,3'-disulfobuty1-5,5'-diphenyl-9-ethyloxacarbocyanine (Oc) in aqueous solution in the presence of NaCl, Mg(NO3)(2), D/L-tartaric acids, asparagine, proline, DNA, and proteins, such as lysozyme, trypsin, RNase, and gelatin. J-aggregates, which are formed in the presence of chiral additives, are optically active and characterized by sigmoidal kinetics with half-times of 10-1000 s, resonance fluorescence, and large CD amplitudes being up to 2 degrees for Tc. Generally, the induced CD signals of the J-aggregates of both dyes are bisignate and the sign corresponds to that of the additive. The transfer of chirality information occurs in the course of the J-aggregation.