It is demonstrated that the polymers obtained in batch polyrecombination reactions have a Schulz-Flory molecular weight distribution. Much wider distributions are obtained if the reaction is carried out in continuous stirred tank reactors. This article is a supplement to “Dimerisation and oligomerisation by dehydrogenation as a general synthetic principle1”. † Theoretically the inequality (46) can always be satisfied, the only condition is that 2a and thus 2NV must be sufficiently large.