A colored supramolecular charge-transfer (CT) host complex composed of racemic rac-[9,9 '-biphenanthryl]-10,10 '-diol, having a large and widely pi-conjugated phenanthrene ring, as an electron donor and 2,5-dimethyl-1,4-benzoquinone as an electron acceptor has been developed. The molecular recognition properties (guest inclusion behavior and color) of the CT complex can be tuned by using electron donor molecules with different steric bulkiness and electron-donating properties.