  Non-Hermitian effects could create rich dynamical and topological phase
structures. In this work, we show that the collaboration between lattice
dimerization and non-Hermiticity could generally bring about mobility edges and
multiple localization transitions in one-dimensional quasicrystals.
Non-Hermitian extensions of the Aubry-Andr\'e-Harper (AAH) model with staggered
onsite potential and dimerized hopping amplitudes are introduced to demonstrate
our results. Reentrant localization transitions due to the interplay between
quasiperiodic gain/loss and lattice dimerization are found. Quantized winding
numbers are further adopted as topological invariants to characterize
transitions among phases with distinct spectrum and transport nature. Our study
thus enriches the family of non-Hermitian quasicrystals by incorporating
effects of lattice dimerization, and offering a convenient way to modulate
localization transitions and mobility edges in non-Hermitian systems.
