A stage-gated, orientation-first roadmap for quasi-one-dimensional (quasi-1D) photovoltaics is presented, translating the established Sb 2 S 3 developmental trajectory to the emerging SbSI family (SbSI, SbSeI, BiSI, and related alloys). The focus is on chain- or ribbon-based absorbers, where charge extraction is governed by thin-film texture and microstructural orientation rather than by interface engineering alone. Sb 2 S 3 is established as a quantitative reference system to define the structural basis of an orientation-first design logic, in which a texture coefficient (TC) threshold for extraction-aligned planes (TC(hk1) > 2) is treated as a causal prerequisite for high performance. The transferability boundary between the purely covalent Sb 2 S 3 framework and iodide-containing SbSI-family chalcohalides is delineated, framing SbSI development as an explicit validity test of the "Sb 2 S 3 -like stability" assumption. A key differentiator is the possibility of halide-ion motion under operating bias, which can shift SbSI from a rigid, vacancy-limited regime to a perovskite-like, ion-migrating regime requiring bias-tolerant device architectures and ion-suppression strategies. The roadmap condenses transferable model rules into a five-gate cascade: (i) film-formation pathways; (ii) an orientation-engineering toolbox; (iii) architecture selection; (iv) defect–stability classification; and (v) extension to SbSeI and Bi-containing alloys. To bridge laboratory Technology Readiness Levels (TRL) with industrial Scale Readiness Levels (SRL), manufacturability checkpoints based on established thin-film standards are embedded. Finally, indoor energy harvesting at ~1000 lux is positioned as a validation gate for leakage suppression, treated as a prerequisite for outdoor durability and energy-autonomous Internet of Things (IoT) deployment.