2,4-Di-(2＇-vinyloxyethoxy)benzylidenemalononitrile (2a), methyl 2,4-di-(2＇-vinyloxyethoxy)benzyli denecyano acetate (2b), 3,4-di-(2＇-vinyloxyethoxy)benzylidenemalononitrile (4a), and methyl 3,4-di-(2＇-vinyloxyethoxy)benzylidenecyanoacetate (4b) were prepared by the condensation of 2,4-di-(2＇-vinyloxyethoxy)benzaldehyde (1) and 3,4-di(2＇-vinyloxyethoxy) benzaldehyde (3) with malononitrile or methyl cyanoacetate, respectively. Trifunctional vinyl ether monomers 2 and 4 were polymerized readily by free radical initiators to give optically transparent swelling poly(vinylethers) 5 and 6. Polymers 5 and 6 wen not soluble in common organic solvents such as acetone and DMSO due to crosslinking. Polymers 5 and 6 showed a thermal stability up to 300 degrees C in DSC thermograms.