A review of the substitution reactions of dibenzofuran as been made. Both mono- and disubstitution reactions have been considered. The orientation of the nitration product of 3-acetaminodibenzofuran has been confirmed; and the structure of the bromination product of the 3-acetamino derivative has been established;Several N-substituted 3-aminodibenzofurans have been prepared for physiological tests. It has been shown that the Skraup reaction on aminodibenzofurans produces two isomeric pyrido-derivatives. Other derivatives in which the amino group was attached to side chains of various types in dibenzofuran have been synthesized and tested;The pharmacological reports revealed that the dibenzofuran derivatives investigated in the study are relatively toxic and that they possess physiological action of meagre therapeutic importance. It is, however, significant that the 4-aminodibenzofuran and 4-acetaminodibenzofuran show analgesic action.