We report the synthesis, characterization, and photophysical and electrochemical properties of a series of luminescent rhenium(l) diimine indole complexes, [Re(N-N)(CO)(3)(L)](CF3SO3) (N-N = 3,4,7,8-tetramethyl-1,10-phenanthroline (Me-4-phen), L = N-(3-pyridoyl)tryptamine (py-3-CONHC2-indole) (1a), N-[N-(3-pyridoyl)-6-aminohexanoyl]tryptamine, (py-3-CONHC(5)HjOCONHC(2)H(4)-indole) (1b); N-N = 1,10-phenanthroline (phen), L = py-3-CONHC2H4-indole (2a), py-3-CONHC5H10CONHC2H4-indole (2b); N-N = 2,9-dimethyl-1,10-phenanthroline (Me-2-phen), L = py-3-CONHC(2)H(4)indole (3a), py-3-CONHC5H10CONHC2H4-indole (3b); N-N = 4,7-diphenyl-1,10-phenanthroline (Ph-2-phen), L = py-3-CONHC2H4-indole (4a), py-3-CONHC5HjOCONHC2H4-indole (0)), and their indole-free counterparts, [Re(N-N)(CO)(3)(py-3-CONH-Et)](CF3SO3) (PY-3-CONH-Et = N-ethyl-(3-pyridyl)formamide; N-N = Me-4-phen (1c), phen (2c), Me2-phen (3c), Ph-2-phen (4c)). The X-ray crystal structure of complex 3a has also been investigated. Upon irradiation, most of the complexes exhibited triplet metal-to-ligand charge-transfer ((MLCT)-M-3) (d pi Re) -> pi(star) (dimine)) emission in fluid solutions at 298 K and in low-temperature glass. However, the structural features and long emission lifetimes of the Me4-phen complexes in solutions at room temperature suggest that the excited state of these complexes exhibited substantial triplet intraligand ((IL)-I-3) (pi -> pi(star)) (Me-4-phen) character. The binding interactions of these complexes to indole-binding proteins including bovine serum albumin and tryptophanase have been examined.