Embodiments in accordance with the present invention encompass compositions comprising a long shelf stabilized organopalladium compound of formula (I) as described herein. The composition further contains a photoacid generator, a photosensitizer and one or more olefinic monomers as described herein. The shelf life of the compositions can further be extended by employing a stabilizer, such as for example, a hindered amine. The composition undergoes vinyl addition polymerization when it is exposed to a suitable actinic radiation to form a substantially transparent film or a three dimensional object. More specifically, the compositions of this invention are stable at room temperature for several days to several months and can also be stored at higher temperatures from about 40° C. to 60° C. for several days and undergo mass polymerization only when subjected to suitable actinic radiation. The monomers employed therein have a range of optical and mechanical properties, and thus these compositions can be tailored to form films and/or three dimensional objects having various opto-electronic properties. Accordingly, compositions of this invention are useful in various applications, including as coatings, encapsulants, fillers, leveling agents, sealants, adhesives, among others.