Bisphenols substantially free of by-products, are produced rapidly by reacting a phenol and a compound of the formulae: ##STR1## wherein R and R' are hydrogen, lower alkyl or aryl; X is lower alkoxy or the same as X'; Y is chlorine or the same as X; X' is aryloxy; Z is a 1,2- or 1,3-propylenedioxy (that may optionally carry hydroxy, lower alkyl or lower hydroxyalkyl substituents), or arylenedioxy radical; n is integer from three to nine; m is (n-1).