How do I lookup a polymer by its structure? This is more of a meta-chemistry question, but, here goes...

Given the structure of a polymer, how can I search online for which polymer it is?

Specifically, I have an image like this:



I'd also like to know which polymer specifically this is, but also a method for figuring this out in the future by myself :)
That looks like bilirubin, from hemoglobin catabolized in the liver  Monomer, dimer..tetramer...oligomer...polymer...high polymer.  It is a tetrapyrrole, not even an oligomer.