A compound including two or more partial structures shown by the following general formula (1-1) in the molecule, wherein each Ar independently represents an aromatic ring optionally having a substituent or an aromatic ring that contains at least one nitrogen atom optionally having a substituent, and two Ars are optionally bonded with each other to form a ring structure; the broken line represents a bond with an organic group; B represents an anionic leaving group that is capable of forming a reactive cation due to effect of either or both of heat and acid. This provides a compound that is capable of curing under the film forming conditions in air or an inert gas without forming byproducts, and forming an organic under layer film that has good dry etching durability during substrate processing not only excellent characteristics of gap filling and planarizing a pattern formed on a substrate.