Three-dimensional inkjet printing of a thermally stable object

A formulation system usable in additive manufacturing of a three-dimensional object that comprises, in at least a portion thereof, a cyanate ester-containing polymeric network, and additive manufacturing processes employing the formulation system are provided. Also provided are objects obtainable by the additive manufacturing and kits containing the formulation system. The formulation system includes a first modeling material formulation which includes a first curable material which is a thermally-curable cyanate ester and a second modeling material formulation which comprises an activating agent for promoting polymerization of the cyanate ester and is devoid of the first curable material, and further includes a second curable material which is different from the first curable material, and optionally an agent for promoting hardening of the second curable material.