The emission spectrum of InBr molecule has been recorded in the region 350-400 nm on BOMEM DA8 Fourier transform spectrometer at an apodized resolution of 0.06 cm −1 using microwave excitation technique. About 61 violet degraded and single headed bands have been recorded and are classified into two band systems, viz. A 3 Π0-X 1 Σ + and B 3 Π1-X 1 Σ + . A few new bands have been observed and are fitted in the vibrational schemes of the two systems. Revised vibrational constants have been determined. The vibrational assignments have been confirmed by observing isotope effect due to InBr 81 in the 30 bands of the A 3 Π0-X 1 Σ + system and 19 bands of the B 3 Π1-X 1 Σ + system. The analysis is further supported by calculating the Franck-Condon factor for InBr 79 and InBr 81 molecules. The following vibrational constants (in cm −1 ) have been determined from the analysis:A 3 Π0-X 1 Σ + system: ν00 = 26599.1 ω e = 226.42, ω e x e = 1.24 cm −1 , ω e = 221.19, ω e x e = 0.528 cm −1 . B 3 Π1-X 1 Σ + system: ν00 = 27380.52 ω e = 223.086, ω e x e = 1.446 cm −1 , ω e = 221.19, ω e x e = 0.528 cm −1 .