One of the grand challenges in the physical sciences is fabricating materials with a defect-free controlled structure on the submicron scale. Realisation of this challenge will significantly advance technologies in a wide range of areas including healthcare and sustainable materials. This project investigates novel methodologies for creating structured systems on a submicron scale from the assembly of complementary building blocks. In our system, small molecule synthetic compounds (host and guest building block molecules) undergo recognition in aqueous media (host and guest fit like lock and key). This event triggers a subsequent process whereby many building blocks get together in a concerted fashion and self-assemble into larger structures including submicron platelet-like aggregates and micron-size long fibres, which may find application as viscosity modifiers or drag reducers.