{As2Mo18} cluster attracts 14 bimyb ligands at its periphery via weak interaction.
The ligands are further embraced by 22 Dawson anions to form 3D supramolecular nets.
Compound 1 represents the highest connectivity of Dawson molybdoarsenate.
Compound 1 shows bifunctional electrocatalytic behavior.
Compound 1 exhibits highly-efficient degradation ability for MB under UV light.