I can help you on this question.
Socrateaser is correct, this is likely a complicated one - to some extent.
If the company has been legally dissolved it is likely the company assets, including IP, have been sold. IF the patents have not been sold to a third party, then you still have a window of opportunity to obtain your assignments.
If the IP are patents, Here is what I would do:
(0) I would search the patent assignment database to see if some third party entity has already been given ownership to the patents. Below is the link.
If new patent assignments have not been recorded, you are in an OK position. You can still get the assignment as the first to register their assignment wins (if such is an issue - a third party may believe they own the patents but if they have not recorded their assignments such assignments are not perfected).
(1) Identify the entity/person handling the dissolution and get his/her/its contact information.
(2) I would submit my documentation to the entity in (1) proving my position that the IP was not assigned as previously agreed.
(3) I would submit a standard assignment agreement to the entity in (1) for approval. Such agreements are fairly common and uncomplicated and you can find examples on the internet.
(4) Once approved by the entity in (1), I would register the assignment document with the USPTO ASAP. To do this one uses the EPAS system.
Here is link:
(at the bottom of the page will be a link titled:
" Please click here to access the EPAS forms").
Now (4) is a VERY important step and FREE if you do it yourself.
If the IP includes Trademarks and Copyrights, we need to tweak the above process a little.
(a) If you need help because some other entity now has ownership of patents that should have been assigned to you - such issue is likely more complicated than can be resolved on JustAnswers.
(b) If you need help obtaining a sample assignment document, I can point you in the right direction.
(c) If you have obtained the signed assignment documents and simply need help registering same, I can help walk you through that process.
If there are other issues or you have additional question, please ask questions until you are satisfied.