Cyanine dyes are a class of popular imaging probes for diagnosis of cancer and monitoring the process of therapy, especially for cyanines with aggregation-induced emission (AIE). Herein, a series of butterfly-shaped cyanine dyes were synthesized facilely by a two-step reaction and they exhibit higher fluorescence intensity in aggregate states than in dilute solutions, manifesting AIE characteristics. The solid-state emissions of the cyanine dyes can be reversibly turned “on” and “off” by grinding-fuming (or recrystallization) with high contrast. Although these dyes comprise the same chromophore, the rotatable aromatic rings introduced on the cyanine skeleton and the alkyl groups on the pyridinium units play important roles in their photophysical properties and stimuli-responsive properties. Interestingly, these cyanine dyes could differentiate cancer cells from normal cells and target mitochondria in cancer cells with super selectivity and high signal-to-noise ratio. Moreover, the cyanine nanoprobes displayed tumor-targeting ability in tumor-bearing mice, manifesting potential application in tumor monitoring.