The picosecond time-resolved infrared spectrum of 4-(dimethylamino)benzonitrile (DMABN) has been recorded in the fingerprint region in acetonitrile solution. Several induced infrared bands have been obtained. From the temporal behavior of the band intensities, the induced bands have been attributed to the S-1 state of DMABN that is believed to be an intramolecular charge-transfer excited state. Vibrational assignments of the observed bands and the molecular structure of the SI species are discussed. Most of the strong bands have been found in the single bond wavenumber region. From this result, the ring C-NMe2 bond is considered to retain a single bond character in the S-1 state. No distinct infrared band that can be assigned to the locally excited state of DMABN has been observed. Measurements are also tried for 4-aminobenzonitrile in acetonitrile, but no induced infrared band has been found.