Lanthanide complexes make it possible to integrate vibrational and luminescence-based chiroptical techniques, opening new possibilities for multimodal structural characterization of biomolecules. Raman optical activity (ROA), which efficiently probes molecular chirality in solution, can be recorded simultaneously with circularly polarized luminescence (CPL).^[1] Weak electronic circular dichroism signals are also sometimes detectable.^[2]
In the lanthanide-aided ROA-CPL detection scheme, lanthanide complexes serve as sensitive chiroptical reporters of molecular conformation and supramolecular organization. They also facilitate chemical imaging because the narrow lanthanide emission bands may not interfere with Raman peaks. This permits the simultaneous acquisition of vibrational and luminescence signals, e.g. in confocal microscopy.^[3]
 We showed that this multimodal spectroscopy is capable of monitoring multiple aspects of collagen chirality.^[4] The dipicolinic acid-based Eu³⁺ complex both affects and ‘senses’ the collagen self-assembly process. It simultaneously acts as a luminescent probe, chiroptical reporter, and a Raman-compatible tag.^[5] The results provide new insight into collagen fibrillogenesis, and establish a proof-of-concept framework for studying protein aggregation or other biomacromolecular assemblies through multimodal chiroptical analysis.