Porphyrins are prized components of functional systems and assembled structures because of their remarkable photophysical, electrochemical, and catalytic properties in both designed and natural systems. [1] Accordingly, much effort has been directed toward the covalent and noncovalent modification of porphyrins and their incorporation into larger more complex and functional systems. For example, covalently modified porphyrins have been exploited in the preparation of enzyme-mimetic catalysts for oxidation reactions, [2] as sensors for a variety of analytes, [3] and as a component of artificial photosynthetic systems. [1] The noncovalent assembly of porphyrins has been exploited in numerous ways, including as a means to control transport in molecular wires, to control energy migration, and to build catalysts. [4] Of particular relevance to our studies are reports on the encapsulation of porphyrins inside self-assembled coordination cages, calixarenes, and cyclodextrins. [5] We, and others, have been studying the synthesis and recognition properties of the cucurbit[n]uril family (CB[n]) [6, 7] of molecular containers. These CB[n] molecular containers possess remarkable binding affinities and selectivities (K a values up to 10 12 m À1 ; K rel values up to 10 6 ) [8] and high environmental responsiveness which render them useful as a component of molecular machines, sensors, and biomimetic systems. [9] We wondered whether it would be possible to combine the advantageous chemical, photochemical, and catalytic properties of the porphyrins with the binding properties of the CB[n] family in a noncovalent fashion. [10] For this purpose we elected to use CB[10] [7e] -with its Scheme 1. Structure of compounds used in this study.