The quenching rate constants of singlet oxygen (¹O₂) by cubane and cubane derivatives were determined. Two methods were used for the generation of singlet oxygen: decomposition of endoperoxide (shown) and photosensitization (tetraphenylporphyrin, TPP, exc. = 532 nm). Both methods gave similar quenching rate constants for cubane and its derivatives. The bimolecular quenching rate constant was unexpectedly higher (10⁴-10⁵ M^-1s^-1) than what is expected for aliphatic alkanes. This can be explained by the combination of two different deactivation mechanisms: energy transfer to cubane C-H vibrational modes and the formation of a charge-transfer complex between ¹O₂ and cubane (¹O₂^•−···cubane^•+).