The suadimins A-C (1-3) from Melodinus suaveolens are the first example of monoterpenoid quinoline alkaloid dimers featuring an unprecedented carbon skeleton. Their structures and absolute configurations were established on the basis of extensive spectroscopic analyses, electric circular dichroism (ECD), and X-ray crystallography. Suadimin A showed significant antimycobacterial activity in vitro with an MIC90 of 6.76 mu M against the H(37)Rv strain of M. tuberculosis.