Distribute in membranes and membrane structures within the cytoplasm of living cells. Barton and co-workers investigated a series of phosphorescent ruthenium complexes with different ancillary ligands that selectively stain the cytoplasm. The groups of Li and Lo have developed a series of cationic iridium complexes as phosphorescent probes for luminescence staining of the cytoplasm of living cells. Iridium complexes with d6 electronic structures often possess excellent photophysical properties such as tunable excitation and emission wavelengths, high luminescent quantum yields, and relatively long phosphorescence lifetimes. Iridium complexes have received considerable attention in inorganic photochemistry, phosphorescent materials for optoelectronics, chemosensors, biolabeling, live cell imaging, and in vivo tumor imaging. As part of our continuous efforts, the cyclometalated iridium solvato complex has been utilized as a selective luminescent switch-on probe for histidine/histidine-rich proteins and a dye for protein staining in sodium dodecyl sulfate polyacrylamide gels. Subsequently, Li and co-workers reported iridium solvato complex as a luminescence agent for imaging live cell nuclei. Thus, we were interested to investigate the effect of varying the extent of conjugation of the C��N co-ligand on the photophysical properties of this type of complex. We herein report the application of iridium solvato complex for the detection of histidine/histidine-rich proteins and for luminescence imaging in cells. We demonstrate that the complex is successfully taken up by both living and dead cells and can function as a selective luminescent probe for cytoplasmic staining. We also investigated the application of iridium complex 1 for staining fixed cells. HeLa cells fixed with 4% paraformaldehyde exhibited strong intracellular luminescence in the cytoplasm upon incubation with complex 1. Similar to the results with live cells, only weak luminescence was observed in the nucleus of the fixed cells. These results suggest that complex 1 is an effective luminescent cytoplasmic stain for both living and dead cells. Vascular endothelial cells, which form the inner surface of blood vessel wall, serve important homeostatic functions in maintaining the vascular physiological states. EC functional changes, such as abnormal permeability, proliferation, apoptosis, alignment, production of chemotactic molecules, and expression of adhesion molecules, etc., play significant roles in many vascular diseases. ECs are exposed to mechanical stimuli in vivo, including shear stress caused by the dragging frictional force of blood flow, and cyclic strain resulting from the repetitive deformation of the cells as the arterial wall rhythmically distends and relaxes with the pulsatile pressure. It has been shown that physiological mechanical stimuli are essential to EC homeostasis, while mortality for each treatment in comparison with the treatment having the lowest rate by calculating odds-ratio statistics pathological mechanical stimuli contribute to the development of vascular disorders during hypertension, atherosclerosis, thrombosis, in-stent restenosis, and bypass graft occlusion, etc.. In the pathological process of hypertension, cyclic mechanical strain subjected to the arterial wall increases accordingly. Cyclic strain of brachial arteries is about 5% in normal state and can be elevated to 15% in hypertension. Abundant evidence reveals that abnormal growth and survival of ECs play key roles in vascular remodeling during hypertension, and elevated cyclic strain exerts complicated effects in this process.