Solid-state reactions of palladium(II) and platinum(II) chloride complexes with imidazole (Him) and pyrazole (Hpz) or their hydrochloride salts are shown to produce metal complex salts and coordination compounds. Thus, K-2[MCl4] or MCl2 can be ground with imidazolium chloride ([H(2)im]Cl) to produce the salts [H(2)im](2)[MCl4] (M = Pd, 1; Pt, 5), which can then be dehydrochlorinated in the solid state to produce the coordination compounds trans-[PdCl2(Him)(2)] 3 or cis-[PtCl2(Him)(2)] 6. The complex cis-[PdCl2(Him)(2)] 2 is produced when Pd(OAc)(2) is ground with [H2im] Cl. Reaction of platinum chloride reagents with imidazole (Him) also produces cis-[PtCl2(Him)(2)] 6, but reaction of imidazole with analogous palladium chloride reagents first produces [Pd(Him)(4)]Cl-2 4 which then slowly converts to trans-[PdCl2(Him)(2)] 3. Grinding pyrazolium chloride with K-2[MCl4] produces [H(2)pz](2)[MCl4] (M = Pd, 7; Pt, 10), which may also be dehydrochlorinated in the solid state to produce the coordination compounds trans-[PdCl2(Hpz)(2)] 8 or cis-[PtCl2(Hpz)(2)] 11. Grinding K-2[PdCl4] or PdCl2 with pyrazole gives [Pd(Hpz)(4)]Cl-2 9, which is then slowly converted into trans-[PdCl2(Hpz) 2] 8. Grinding PtCl2 with Hpz generates [Pt(Hpz)(4)]Cl-2 12, but using K2PtCl4 as the metal source does not generate the same product. The single-crystal structures of 8, a new polymorph of 11 and [H(2)pz](2)[PtCl6]center dot 2H(2)O (isolated as a decomposition product) are reported for the. rst time, and the structures of 5 and 10 have been solved ab ibitio from XRPD data.