Hi,
Ahhh, thanks for the suggestion I have looked at the SMILES data closer and I think it’s a byte instead of a string:

array([b’FC(C1=CC(C(C2=C(S3)C=CC=C2)=CCCN4CCNCC4)=C3C=C1)(F)F’],
dtype=object)>, <tf.Tensor: shape=(), dtype=float64, numpy=186.0>)

I’m going to convert them into strings and see if that helps.
If this doesn’t work I’ll have a look at tokenization, when would tokenization need to be used?
EDIT:
I’ve proceeded with more reading and now understand the error is probably because the input data needs to be tokenized and also padded (index error probably due to the passed sequences not being constant length)
Thank you
A