Iodine adds across both triple bonds of 4,4'-bis-(prop-2-yn--yl-oxy)biphenyl, yielding the 4,4'-bis-(2,3-diiodo-all-yloxy)biphenyl title compound, C(18)H(14)I(4)O(2); the 2,3-diiodo-ally-oxy substituents have the I atoms in an E configuration. In the biphenyl portion of the mol-ecule, the aromatic rings are inclined by 37.8 (2)°.