Using photochemical [2 + 2] cycloaddition, a cyclobutane dione was generated from isophorone, a condensate of bio-acetone. Additionally, hydrodeoxygenation of the dione yielded a mixture of polycyclic alkanes, whose high energy density is appropriate for high perfomance aviation applications. This work outlines a light-based approach to increase the energy density of a potential renewable carbon aviation fuel in high yields and high carbon efficiency without sacrificing performance.