“…The binding of rhodamine B to multidrug‐resistant protein can alter the orthogonality in the electronic transition moments, as reflected by the patterns displayed by induced circular dichroism, the associated absorption spectra, 10 and fluorescence properties 9 . Associations of derivatized rhodamines with proteins should be dominated either by inter–amino acid interactions that can be established within the protein local environment 9,10,12,15,16 or by intramolecular H bonding and intermolecular NH interactions that can condition probes' hydrophobic interactions and preferential location. The latter, earlier addressed 13,14 in rhodamine B, rhodamine 6G, and rhodamine 123, can further provide intrinsic means of probing the dynamics of these interactions in studying biological environments.…”