Pyrene and OTPh are solubilized in separate sites in the NaDC hydrogel since no energy transfer was observed between the excited state of OTPh and ground state pyrene. The singlet excited state lifetimes of conjugated oligomers and polymers are short, and the fluorescence decay for OTPh in NaDC occurs over a much shorter timescale than the 2 µs timescale used to measure the decay of the pyrene fluorescence (Figure ). In addition, the lifetimes for the singlet excited state of pyrene is shorter than the lifetime for the dissociation of guests bound to the primary aggregates of bile salts. Therefore, the singlet excited states of OTPh and pyrene do not relocate during their lifetimes and the emissions from these excited states report on the local binding environment of OTPh and pyrene in the NaDC hydrogel.