In the case of thiophene synthesis, the model cannot identify a suitable template for the simple ring system (Figure , substrate 6), regardless of the dataset used. However, in the more complex case (Figure , substrate 5), it focuses its efforts on the morpholine ring, predicting the shown disconnection (Figure , substrate 5) with a high probability. Whilst this does not indicate that the models cannot predict thiophene formation, it alludes to the fact that these templates may be under represented in the underlying dataset. obtained from the literature employing commonly used ring formations. For each prediction, the patent id or Reaxys id corresponding to the template used has been given as a precedent. In all cases, the probability 'p(x)' of predicting the template for the given compound has been shown, where 'x' refers to the prediction's rank (i.e. 'p(1) = 0.983' means the first prediction with an associated probability of 0.983 In cases where the precursors have been highlighted in a box, the predicted disconnection matches that reported in the literature or is the correct one as identified by expert chemists, the notation is equivalent for consistency. The literature reference from which the compound was obtained is given for each example where appropriate. In cases where the literature reference has not been given, the compound was purposefully simplified to determine if the correct disconnection could be predicted. We have refrained from exhaustively showing all possible disconnections and have chosen the first prediction that can be applied to generate a set of reactants, regardless of whether they reflect the 'ground truth' to show the raw predictions. The model fails to predict the synthesis of thiophenes in this case as it focuses on the morpholine ring for compound 5 and does not have any template matching the molecular environment in compound 6 for the desired outcome.