It was reported in Part I of this series that coatings of various polymers containing cinnamic ester groups are rendered insoluble by exposure to ultraviolet radiation, and that the rate of insolubilization may be increased by the inclusion of certain organic compounds. A continued systematic examination of the behavior of several hundred organic compounds has revealed that the ability to sensitize to some degree is quite general, provided that no complicating factors are present. The sensitivity of poly(vinyl cinnamate) is decreased by the presence of reducing groups in the addend, and sensitizing activity is lowered by interaction between adjacent groups. It is enhanced by the introduction of increasing conjugation and of ketone, nitro, or amino groups. Spectrograms of polymer-sensitizer combinations indicate that, with increasing sensitivity value, the sensitivity shifts towards, and, in some cases, into, the visible portion of the spectrum.