It is our great pleasure to present this special thematic issue based on the papers presented at the 42nd Silicon Symposium held in Long Branch, New Jersey on 9–11 June 2009. The symposium was tailored to provide a forum to all branches of chemistry of silicon and consequently the publications in this issue cover various aspects of silicon chemistry and its application. A brief history of the symposium authored by Professor Bob West is available at the symposium website at www.siliconsymposium2009.com. First of all, we would like to thank the contributors for submitting their cutting edge discoveries for this thematic issue. The breadth and depth of the topics covered indicates a phenomenal growth in the applications of silicon chemistry. The creativity and explorations of new avenues to apply silicon have been hallmarks of silicon chemists because this chemistry plays a critical role in a discipline which links organic, organometallic and materials chemistry. Just to provide a sampler of the issue, in the area of materials tailoring, Mehdi explores polyether functionalization of mesoporous silica, whereas Unno and coworkers apply silicon modified nanoporous alumina for selective adsorption. In the area of medicinal applications, West's group discloses results on the silicon derivatives of indomethacin and their improved anticancer activity, whereas Segal and Lukevics present their findings on the iron oxide-based magnetic nanostructures bearing cytotoxic organosilicon molecules for drug delivery and therapy. In the area of nanoscience, Fink and coworkers describe silicon nanoparticles with tailored surfaces and Chauhan's group presents findings on the long-chain silanes as reducing and stabilizing agents for assorted Pd-particles. In another disclosure, a very interesting application of silane reduction of onium salts is presented by Crivello. As is evident from this list, the ever evolving role of silicon is very actively explored and investigated in the fields such as catalysis, biochemistry, medicine, nano-science and technology. We would also like to take this opportunity to thank all the sponsors for their assistance and contribution as well as reviewers who volunteered their time to review the manuscripts. In addition, we would like to thank Ms Jasmine Cardona, Dr Andy Auerbach, and Professor Nan-Loh Yang of the Center for Engineered Polymeric Materials, three very dedicated people, who have immensely helped us in successfully organizing this conference.