A protein complex that consists of two interferon regulatory proteins (IRFs); may be homodimeric or heterodimeric. The activation of a latent closed conformation of IRF in the cytoplasm is triggered by phosphorylation of Ser/Thr residues in a C-terminal region. Phosphorylation stimulates the C-terminal autoinhibitory domain to attain a highly extended conformation triggering dimerization through extensive contacts to a second subunit.