Herein we report a two-directional cyclization strategy for the synthesis of highly strained depth- expanded oxygen-doped chiral molecular belts of the zigzag-type. From the easily accessible resorcin[4]arenes, an unprecedented cyclization cascade generating fused 2,3-dihydro-1H-phenalenes has been developed to ac- cess expanded molecular belts. Stitching up the fjords through intramolecular nucleophilic aromatic substitu- tion and ring-closing olefin metathesis reactions fur- nished a highly strained O-doped C2-symmetric belt. The enantiomers of the acquired compounds exhibited excellent chiroptical properties. The calculated parallelly aligned electric (μ) and magnetic (m) transition dipole moments are translated to the high dissymmetry factor (j glum j up to 0.022). This study provides not only an appealing and useful strategy for the synthesis of strained molecular belts but also a new paradigm for the fabrication of belt-derived chiroptical materials with high CPL activities.