Compositions and methods are disclosed for imaging tissue or a lymphatic or circulatory system, for example, in the near infrared. Dyes that emit wavelengths in the infrared or near infrared regions of the spectrum may be employed on their own, as combinations or complexed with serum albumin, or as part of a covalent conjugate with serum albumin.
FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT
 The U.S. Government may have certain rights in this invention pursuant to Contract Nos. DMR-9808941 and DMR-0213282 by the Office of Naval Research, and Contract Nos. DE-FG02-01ER63188 and NIH R21EB-00673 by the Department of Energy.