Double [2,3] sigmatropic rearrangements of bis(propargyl sulfenates) to bis(allenic sulfoxides) and of bis(propargyl sulfinates) to bis(allenicsulfones) are shown to be a convenient and effective method for the preparation of conjugated diallene systems bearing two electron withdrawing trihalomethyl sulfoxide or sulfone substituents either on C-1 and C-6, or on C-3 and C-4. Such substituents are further