Magnetization and heat capacity were measured down to 0.4 K in a 2:1 charge-transfer (CT) salt of a new donor molecule, ethylenedithiotetrathiafuIvalenoquinone-1,3-dithiolemethide(1) with a magnetic FeBr4- ion (1(2)(.)FeBr(4)). The Fe(III) d spins of FeBr4-ions were subject to apparently ferromagnetic interaction with each other through the interaction with the pi spins developed by localization of the conducting pi electrons on the donor columns, eventually giving rise to ferrimagnetic ordering (R) near 1 K, which provides the first example in a molecular pi-d system.