Chemical behavior of carbenes (adamantylidenes) generated by photolysis of adamantanediazirines has been investigated while they were incarcerated within an organic container in water and on silica surfaces. Confined carbenes behave differently from the free ones, and their behavior is dictated by the nature and the structure of the host-guest complexes. The substituent present on the adamantyl skeleton controls the stoichiometry (1:1 or 2:2) and the orientation of guest molecules within the host.