Molecular design of near infrared polymethine dyes: A review

•Theory concepts correlated spectral parameters with dyes constitution are reviewed.•Chemical strategies to decrease the HOMO–LUMO energy gap are presented.•Influence of open polymethine chain modifications on light absorption is analyzed.•End-groups with developed π-electron systems affect on frontier levels generation.

The recent advances in molecular design of polymethine dyes absorbing and emitting light in the near-infrared region are reviewed. In contrast to many publications, which concern mostly experimental results, our work describes mainly the theoretical approaches developed to connect the spectral characteristics with the chemical constitution of polymethine dyes. Considering such approaches, molecular design can be based on modern theoretical concepts. This enables the syntheses of new perspective dye molecules with specified spectral properties.