In the presence of an imide compound (e.g., N-hydroxyphthalimide) shown by the following formula (1): wherein R1 and R2 represent a hydrogen atom, a halogen atom, an alkyl group, an aryl group and a cycloalkyl group, and R1 and R2 may bond together to form a double bond, or an aromatic or non-aromatic ring, and Y is an O or OH, and n denotes 1 to 3; a substrate is allowed to contact with at least one reactant selected from (i) a nitrogen oxide and (ii) a mixture of carbon monoxide and oxygen to be introduced with at least one functional group selected from a nitro group and a carboxyl group. The nitrogen oxide includes, for example, a compound represented by the formula NxOy (e.g., N2O3, NO2). The substrate includes, for example, a compound having a methine carbon atom (e.g., adamantane), a compound having a methyl group or a methylene group at an adjacent moiety of an aromatic ring. According to such reaction, the substrate can be efficiently nitrated or carboxylated even in a mild or moderate condition.