DNA binding by intercalation , showing both sequence and enantiospecificity, of a ruthenium diimine complex, is reported by Christine Cardin, Andrew Kellett et al. in their Research Article (e202318863). The right-handed helix seen in the crystal structure shows variable degrees of twisting, including the first intercalation by a ruthenium complex from the DNA major groove. In solution, the lambda enantiomer was found to be more stabilising with a range of DNA sequences.