Nomenclature rules based on the structure and names of monomers are extended to double-strand organic ladder polymers and spiropolymers. The double-strand polymer is defined as the polymer whose molecules are a continuous sequence of cycles with a common atom in neighbouring cycles (spiropolymer) or two or more common atoms (ladder polymer). The structure-based nomenclature consists in the choice of the most suitable repeating constitutional unit (RCU), a multiple of which is the polymer. The rules enable marking of substituents and end groups. The nomenclature based on monomer names includes the starting monomer with the corresponding prefix "ladder" or "spiro".