  Non-interacting particles in non-Hermitian quasi crystals display
localization-delocalization and spectral phase transitions in complex energy
plane, that can be characterized by point-gap topology. Here we investigate the
spectral and dynamical features of two interacting particles in a non-Hermitian
quasi crystal, described by an effective Hubbard model in an incommensurate
sinusoidal potential with a complex phase, and unravel some intriguing effects
without any Hermitian counterpart. Owing to the effective decrease of
correlated hopping introduced by particle interaction, doublon states, i.e.
bound particle states, display a much lower threshold for spectral and
localization-delocalization transitions than single-particle states, leading to
the emergence of mobility edges. Remarkably, since doublons display longer
lifetimes, two particles initially placed in distant sites tend to bunch and
stick together, forming a doublon state in the long time limit of evolution, a
phenomenon that can be dubbed {\em non-Hermitian particle bunching}.
