The brittle nature of ceramic thin film materials is associated with limited dislocation mobility based on their characteristic ionic and covalent bonds. Typical representative are transition metal carbides (TMC) and borides (TMB), well-known for their extreme thermo-mechanical properties. The enhancement of their ductile character is typically pursued by concepts adapting the bonding nature or adjusting the morphological appearance. This talk gives an overview of the assessment and influencing parameters of elastoplastic properties of physical vapor-deposited face-centered cubic TMCs and hexagonal TMBs. In more detail, substitutional alloying by exchanging carbon with nitrogen on the non-metal sublattice to adapt the valence electron concentration (VEC) is proven for group IV to VI TMC as a potential approach enhancing the intrinsic fracture toughness. Furthermore, the influence of structural defects, sub-stoichiometries, different orientations, and grain boundary phases on the mechanical properties of superhard diborides such as TiB2±z, WB2±z, or CrB2±z is investigated thoroughly. For the assessment of diverse fracture characteristics, advanced micro- and nanomechanical testing methods ranging from basic nanoindentation to cantilever bending and pillar compression geometries, as well as instrument in-situ setups, have been utilized. Especially for understanding the fatigue properties of Cr-based ceramics, in-situ micro-mechanical nanobeam diffraction experiments provided insights into the mechanisms dictating their damage tolerance. In addition, for ternary TMBs, insights on high-temperature cantilever bending tests up to 800 °C will be presented.