Tetracene is well known for its high singlet fission (SF) efficiency, which could be used to enhance the energy conversion efficiency in solar cells. However, its photoinstability toward oxygen must be improved before it can be used as a light-harvesting component. In this work, a series of substituted tetracenes were designed to identify tetracene compounds with not only good stability toward oxidation but also small SF activation energies. The stabilities were evaluated using the frontier molecular orbital energies, whereas the SF activation energies were deduced from the energy differences between the first excited singlet state and twice the first excited triplet state. Substitution strategies on tetracene are proposed for the purpose of simultaneously improving stability and reducing the SF activation energy.