The ternary Cu-Bi-S based semiconductor with abundant and environmental-friendly elements may provide alternative choice for near-infrared (NIR) light-emitting sources. High-quality copper bismuth sulfide Cu4Bi4S9 (CBS) nanobelts of controllable lengths up to 1 cm were synthesized through a modified solvothermal route by using solvents of varied boiling joints (BP) and changing reaction temperatures (RI) to control the competition of efficient collision of Cu4Bi4S9 seeds, intermediate species and precursors and growth of Cu4Bi4S9 nanobelts. Their NIR photoluminescence (PL) of Cu4Bi4S9 nanobelts was firstly observed in the range of 1400-2200 nm, which showed the transition characteristics of Mixed direct and indirect-bands nearby. The absorption and PL spectral data could be well accounted for by the ab initio band calculations of Cu4Bi4S9. (C) 2013 Elsevier Ltd. All rights reserved.