The present invention relates to intercalator pseudonucleotides. Intercalator pseudonucleotides according to the invention are capable of being incorporated into the backbone of a 
nucleic acid or 
nucleic acid analogue and they comprise an intercalator comprising a flat 
conjugated system capable of co-stacking with nucleobases of 
DNA. The invention also relates to oligonucleotides or 
oligonucleotide analogues comprising at least one intercalator pseudo 
nucleotide. The invention furthermore relates to methods of synthesising intercalator pseudo nucleotides and methods of synthesising oligonucleotides or 
oligonucleotide analogues comprising at least one intercalator pseudonucleotide. In addtition, the invention describes methods of separating sequence specific 
DNA(s) from a mixture comprising nucleic acids, methods of detecting a sequence specific 
DNA (target DNA) in a mixture comprising nucleic acids and / or 
nucleic acid analogues and methods of detecting a sequence specific 
RNA in a mixture comprising nucleic acids and / or nucleic acid analogues. In particular said methods may involve the use of oligonucleotides comprising intercalator pseudo nucleotides. The invention furthermore relates to pairs of oligonucleotides or 
oligonucleotide analogues capable of hybridising to one another, wherein said pairs comprise at least one intercalator pseudonucleotide. Methods for inhibiting a DNAse and / or a RNAse and methods of modulating transcription of one or more specific genes are also described.