Is it possible to sue or ask for equity after leaving the company - on a bad note, to be added.
I could just threaten to litigate and ex-employer would go ahead and grant me equity. But the thing is that they could screw me in 10 other ways if they give me a stock grant for my work there.
It is possible for me to threaten to torpedo my ex-employers patents
It is also possible for me to lawyer up and send them a cease and desist letter for the same.
It is also possible for me to just torpedo their IP - it will harm my own career, but I could do that.
Now that I got that out of the way, you should definitely NOT go on the offense against your employer by torpedoing their network or threatening to de-legitimize them. If you make the threat against them, then there is no going back. It can be seen as 'extortion' and your employer can go after you.
Be smart about this (specially if you're already in their 'bad books')
Now, if you have legal claim over the patents (I"m guessing that's a big part of this or what you're gunning for) then you should contact a patent lawyer. But I have never in my life heard of someone being able to sue after being fired for equity. You can, however, sue for 'wrongful dismissal' if you feel that your termination was unwarranted.
Lastly, do not torpedo your own career. You will bounce back. Your employer will bounce back. People get let go all the time.
If you do something "stupid" and it costs you your career than you're dead in the water going forward. They will have won and you will have proved nothing. Cut your lose and move on.
It's always possible. The issues are whether it is smart/appropriate and/or whether you have an entitlement to equity and/or whether you have any IP at all (many employment agreements, for example, contain provisions relating to the automatic transfer of IP.) Yes, the company could screw you 10 other ways - but you would enter into a shareholders or stockholders agreement with the other founders to prevent that and to regulate the company. If your likely equity has some value, I would speak to a corporate lawyer (not a patent lawyer). If it has no value...onwards and upwards....