Biphenyl(1) and other compounds of type PhXPh (X = O(19); S(30); NH(33); CH2(40); (CH2)2(41); (CH2)3(51); C(CH3)2(55) were reacted with chlorosulfonic acid. Under forcing conditions (100–150°C), compounds1,19,33,40,41, and55afforded the cyclic sulfones (2,26,27,39,43, and63). Cyclisation occurred most readily with diphenylethane (41) to give the 7-membered sulfone (46). On the other hand, diphenylsulfide (30) and diphenylpropane (51) failed to give cyclic products, while 2,2-diphenylpropane (55) afforded only a low yield of the cyclic compound (63) among a mixture of uncyclised products (57,61,62). With chlorosulfonic acid under milder conditions, the substrates afforded mono-, di, tri- and tetra-sulfonyl chlorides which have been converted into 32 sulfonamides for screening as candidate medicinals and pesticides. The spectroscopic properties of selected compounds are briefly discussed with special reference to the orientation of sulfonation.