The same research group reported a novel heterocyclic porphyrin dimer containing an asymmetrically distorted N-alkylporphyrin as the first host molecule capable of sensing chiral fullerene C76 by means of 1H-NMR spectroscopy [24]. Kim, Inoue, and coworkers used achiral molecular cucurbiturils with significant enantiomeric and diastereomeric discrimination by incorporating a strong chiral binder [25]. (S)-2-methylbutylamine as the strong binder was discriminated by two enantiomeric supramolecular hosts, composed of cucurbituril[6] and (R)- or (S)-2-methylpiperazine. Borhan and coworkers investigated a porphyrin tweezer host with which chiral substrates exhibited exciton-coupled bisignate CD spectra with predictable signs [26].

Absolute configurations of a variety of erythro and threo guests could be clearly determined.

Suzuki and coworkers synthesized a secondary terephthalamide host attached to four aryl blades [27]. A conformational change from a nonpropeller anti-form to a propeller-shaped syn-form upon complexation with ditopic guests results in much stronger chiroptical signals (chiroptical enhancement). Recently, Nakashima et al. reported optical activity and chiral memory effect thiol-capped CdTe nanocrystals by the ligand exchange of Batimastat chiral components with an achiral thiol [28].Color detection on chiral sensing would be a most convenient monitoring system useful for in situ chiral examination, and would contribute greatly to pharmaceutical research fields.

When converting chiral recognition phenomenon into a change of color, the design of the host Cilengitide molecule attached to the chromophore is critical.

Outstanding and pioneering work was performed by Kubo and coworkers who developed a calixarene host carrying two indophenol dye moieties and a binaphthyl group [29]. When a guest molecule such as phenylglycinol was added to the host dissolved in ethanol, the solution color changes depending on the chirality of the guest. The original color of the guest-free host is red, but addition of (R)-phenylglycinol causes a change in color to blue-purple due to a bathochromic shift of the indophenol absorption band (515.5 to 538 nm) together with the appearance of a new band at 652.5 nm. Interaction between the host binaphthyl group and the guest phenyl group induces variation in the hydrophobic environment about one of the indophenol dye moieties with deprotonation of the other indophenol group. In contrast, the solution color remains red upon the addition of (S)-phenylglycinol.