RT Journal Article SR Electronic T1 Optimization and functionalization of red-shifted rhodamine dyes JF bioRxiv FD Cold Spring Harbor Laboratory SP 2019.12.20.881227 DO 10.1101/2019.12.20.881227 A1 Jonathan B. Grimm A1 Ariana N. Tkachuk A1 Heejun Choi A1 Boaz Mohar A1 Natalie Falco A1 Ronak Patel A1 Jennifer Lippincott-Schwartz A1 Timothy A. Brown A1 Luke D. Lavis YR 2019 UL http://biorxiv.org/content/early/2019/12/20/2019.12.20.881227.abstract AB Expanding the palette of fluorescent dyes is vital for pushing the frontier of biological imaging. Although rhodamine dyes remain the premier type of small-molecule fluorophore due to their bioavailability and brightness, variants excited with far-red or near-infrared light suffer from poor performance due to their propensity to adopt a lipophilic, nonfluorescent form. We report a general chemical modification for rhodamines that optimizes long-wavelength variants and enables facile functionalization with different chemical groups.