N-Carbomethoxynorcodeinone (1b) was found to be unreactive to photolysis in benzene solution, but irradiation (366 nm) in the presence of methanol, water, ethanol, or n-propyl alcohol gave the rearranged and solvent-incorporated phenols 13a-d. Under comparable photolysis conditions, N-carbomethoxynordihydrocodeinone (33) did not photorearrange at 366 or > 300 nm. Spirocyclopropane 15b is proposed to be an intermediate in this photorearrangement; addition of ROH to 15b occurs by nucleophilic attack with inversion of configuration at the cyclopropane carbon atom most able to stabilize a positive charge. In the absence of a suitable nucleophile (benzene or t-BuOH solutions) 15b reverts to 1b. Irradiation of the C(5)-methyl-substituted codeinone derivative 17a in methanol solution did not result in solvent incorporation, but rather gave the benzopyran 21a in quantitative yield by way of the intermediate dienone 20a. The carbamate 17b gave separable mixtures of 20b and 21b; dienone 20b was converted to benzopyran 21b in quantitative yield by treatment with diethylamine in CH2Cl2. Additional examples of this tandem photorearrangement-hydrogen atom transfer-intramolecular conjugate addition are described; e.g., 22 --> 24 and 25 --> 26. Photolysis of 1b in the presence of acetic acid gives a mixture of the solvent-incorporated phenol 27 and 8,9-dihydro-2-methoxy-7-carbomethoxydibenz[d,f]azonine-1,13-diol (28). The less nucleophilic oxalic acid provides a route to 28 free of solvent-incorporated products analogous to 27. The facial specific photoadditions of THF to enones 13b and 1b to give 30 and 31 occur by hydrogen atom transfer from C(2) of THF to the photosubstrate followed by radical coupling at the beta-position of the enone. The molecular structure and novel crystal packing arrangement of the monohydrate of 30 were determined by an X-ray diffraction study. Enones 1b and 17b also undergo SET-type photoreductions in the presence of triethylamine (TEA) to give alpha-thebainone derivatives 32a and 32b. A mechanism is proposed to account for photoproduct distributions when irradiations are carried out in the presence of varying amounts of both methanol and TEA. It was found that codeine is as effective as TEA in promoting the photoreduction of 1b to the alpha-thebainone derivative 32a. Opportunities for the utilization of the photochemistry of modified morphine alkaloids for approaches to opiate receptor photoaffinity labeling and the provision of new substrates for opiate receptor affinity studies are briefly discussed.