We showed previously that unsupported catalysts prepared from amine thiomolybdates incorporated with bivalent metals (Fe, Ni, Co) are highly active for hydrodenitrogenation (HDN) and hydrodesulfurization (HDS). In particular, an iron-promoted molybdenum sulfide catalyst gives a much higher HDN-to-HDS activity ratio than commercial supported catalysts. The present study examines trivalent chromium as a promoter for MoS2. The catalyst precursors are synthesized via two routes: one involves olation, the other chelation. Tests with a catalytic cycle oil show that the behaviors of the Cr-containing catalysts prepared from the two routes are qualitatively similar. Chromium is a more effective HDN promoter than iron. The Fe0.5Cr0.5Moy (1 <= y <= 1.5) trimetallic sulfide is more active and selective for HDN than FeMo and CrMoy bimetallic sulfides. The predominant phase in the chromium-containing catalysts comprises nanocrystalline MoS2 and amorphous Cr2S3. (C) 2012 Elsevier B.V. All rights reserved.