Herein, relationships between the structures of 1-aminoethyl-substituted chromenes and their antimalarial activities were thoroughly investigated. At first, the methyl moiety in the side chain was removed to eliminate chirality. The hydrogenation state of the benzopyran system, the position of the phenolic OH moiety, and the distance of the basic amino moiety toward both aromatic rings were varied systematically. 1-Benzopyran-5-ol <b>8b</b> (IC<sub>50</sub> = 10 nM), 1-benzopyran-7-ol <b>9c</b> (IC<sub>50</sub> = 38 nM), and the aminoalcohol <b>19c</b> (IC<sub>50</sub> = 17 nM) displayed antiplasmodial activity with IC<sub>50</sub> values below 50 nM. To identify the mechanism of action, inhibition of three key enzymes by <b>9c</b> was investigated. <b>9c</b> was not able to reduce the number of <i>Plasmodia</i> in erythrocytes of mice. This low in vivo activity was explained by fast clearance from blood plasma combined with rapid biotransformation of <b>9c</b>. Three main metabolites of <b>9c</b> were identified by liquid chromatography-mass spectrometry (LC-MS) methods.