An alternating chain of a paddlewheel [Ru-2(II,III)(O2CEt)(4)](+) (EtCO2- = propionate) complex and [Pt(mnt)(2)](-) (mnt(2-) = maleonitriledithiolate) has a ferrimagnetic spin arrangement of S = (3)/(2) and (1)/(2) local spins, respectively, as well as three-dimensional antiferromagnetic ordering with a canting mode at 8.6 K. This chain is stacked at the [Pt(mnt)(2)](-) units to form a slipped column in the vertical direction against the chain, which acts as a pathway for electrical conduction.