Live-cell imaging that combines multiple modalities had grown to be an essential technique in biological studies. In this context, we have focused on second harmonic generation (SHG) imaging technique, and have developed novel dyes that generate SHG signal but no fluorescence signal. SHG imaging technique has been shown to be useful in analyzing biological phenomena, the all dyes used so far for SHG imaging emit fluorescence and therefore multimodal imaging of these had been difficult. When the cell was stained directly with one of the dye, only SHG signals were detected without any fluorescence signal, indicating that these SHG-specific dyes do not interfere with fluorescence images of other fluorescent dyes. Therefore, with this new SHG specific dye, SHG and fluorescence imaging can be performed simultaneously without interference, enabling true multimodal imaging of biological phenomena for the first time.