As L. Light company made biliverdin was hard to dissolove in the usual solvents, spectrochemical studies were made in which characteristic infrared absorption spectra were noted. L. Light company made biliverdin was dissolved in 5% potassium hydroxide alcohol and was acidified at about pH 4.6 with N/10 hydrochloric acid after 5"s waterbath, and thus an ether extractable substance was obtained. This green colored ether extractable substance proved qualitative reaction for biliverdin and exhibited the absorption maximum at 700 and 375 mμ. in the glacial acetic acid. In the infrared absorption spectra of the ether extractable biliverdin, the following features were observed with that of L. Light company made biliverdin. 1) The OH, NH streching vibration (VOH, NH) was observed at 2.90 and 3.11μ. 2) The C=O streching vibration of the carbonyl group ((v)C=O) was observed at 5.83.μ. 3) The C=C streching vibration of the vinyl group ((v)C=C) was observed at about 6.4μ. 4) Absorption band due to conjugated double bond aromatic ring vibration was observed at about 6.20μ. In consequence, the ether extractable biliverdin provided the chemical structure of biliverdin which was established by H. Fisher and R. Lemberg. On the other hand, L. Light company made biliverdin presumably had some combination radicals although it had carboxyl ion. It was not clear regarding NH and vinyl radicals.