Pentacene　has　been　actively　studied　as　relevant　materials　in　organic　field-effect　transistors　(OFETs)　and　organic　light-emitting　diodes　(OLEDs).　However,　the　low　solubility　and　low　stability　of　pentacene　in　common　organic　solvents　have　hindered　its　applications.　When　exposed　to　light　or　at　high　concentration,　pentacene　is　found　to　dimerize　easily.　Many　research　groups　are　currently　working　on　the　design　and　synthesis　of　novel　substituted　pentacenes,　but　few　of　them　systematically　reported　physical　properties　such　as　molecular　spectroscopy　and　electronic　properties,　which　might　elucidate　the　influence　of　substituents　on　HOMO-LUMO　gaps.　Furthermore,　the　reactive　nature　of　the　central　ring　in　pentacenes　makes　pentacenes　good　dienes　for　Diels-Alder　reactions.　In　this　paper,　a　series　of　soluble　6,13-disubstituted　2,3,9,10-tetrakis(trimethylsilyl)pentacenes　were　synthesized　and　characterized.　Their　reactions,　structures,　and　physical　properties　were　also　studied.　In　addition,　bulky　o-carboranyl　substituted　pentacene　derivative　15　and　6-chloro-2,3,9,10-tetrakis(trimethylsilyl)pentacene　(16)　were　synthesized　for　the　first　time.　Compound　16　possesses　the　largest　dihedral　angle　(7.7°　with　two　adjacent　benzene　rings)　and　shows　a　wave　structure.　Diels-Alder　reactions　with　acceptable　efficiency　were　carried　out　between　16　and　various　dienophiles.　©　2007　Elsevier　Ltd.　All　rights　reserved.