Several poly(ionic liquids) have been synthesized based on poly(1-vinyl-3-tert-butoxycarbonylmethylene imidazolium) salts with different counterions to investigate the tert-butyl ester pyrolysis of these compounds. It is found that the counterions strongly influence the temperature of the pyrolysis. The pyrolysis temperature shifts to higher or lower temperatures depending on the nature of the counterions. The use of microwave irradiation was employed to accelerate the gas release because of the high dipolar interaction of amorphous salts with microwaves. The result of these reactions is the formation of organic foams that could be of industrial interest.