Achieving reversible thermochromism of bisdiynamide polydiacetylene via self-assembling in selected solvents

•Polydiacetylene with two alkyl tails was prepared by self-assembling in water or alkanes.•Water medium hinders the growth of lamellar structure, causing irreversible thermochromism.•Alkane medium promotes molecular organization within the assemblies.•The increase of molecular ordering and particle size yields reversible thermochromism.•Molecular arrangement within the assemblies is probed by various techniques.