Polymers with both low water uptake and a low dielectric constant have seen interest from both the electronic and microelectronic industries for several years. They play a crucial role in maintaining the good operating situation of devices, whereas most other materials are unsatisfactory. In this contribution, two new fluoropolymers are reported, which are derived from the thermo-crosslinking reaction of functional monomers containing perfluorocyclobutane and benzocyclobutene moieties. These polymers show water uptake ranging from 0.11 to 0.31% after immersion in boiling water (near 98 degrees C) for 96 h, and exhibit dielectric constants (k) of below 2.4 at a range of frequencies from 0.1 MHz to 30 MHz. In contrast, a comparative polymer without perfluorocyclobutane units has a k value of more than 2.70 and water uptake of 0.67%, respectively, suggesting that the low water absorption and dielectric constants of the fluoropolymers can be attributed to the existence of perfluorocyclobutane groups in the molecular backbone. These results also indicate that the properties of the fluoropolymers are superior to these of the most commercial polymeric low-k materials, implying that these fluoropolymers could be used as the varnish for enameled wire in the electrical industry and as encapsulation resins in the microelectronics industry.