Abstract The assignment of the carbon-13 nmr resonances of a series of oxetanes derived from the photoaddition of benzophenone and 2-naphthaldehyde to furan and some of its methyl derivatives and of benzophenone to 2, 5-dimethylthiophene has been made. The assignments were made by chemical shift arguments, by the use of C-13 labelling when required and different decoupling techniques. This information may be useful in the ...