<p>The [2+2] photopolymerization of bisolefinic monomers is an important method for the synthesis of polymeric materials. However, these processes are usually carried out in solid states under the irradiation of high-energy UV light, while the corresponding [2+2] polymerization in solution has proved to be inefficient due to the lack of preassembly of the monomers. Herein, we demonstrate that the [2+2] polymerization of <i>p</i>-phenylenediacrylate monomers can be achieved in solution under visible light by employing energy transfer catalysis with 2,2′-methoxythioxanthone as a photocatalyst. Because no preassembly is required, this solution polymerization is applicable to <i>p</i>-phenylenediacrylate monomers with different ester groups, affording a series of cyclobutane-imbedded full-carbon chain polymers with high thermal stability, good solubility, and processibility. In addition, by virtue of the reversibility of the photo [2+2] cycloaddition, this [2+2] photopolymerization product can also undergo depolymerization to lower molecular weight polymers, suggesting the potential of this class of photopolymerization in the development of closed-loop chemical recyclable polymers.</p>