Isonicotinic acid hydrazide in ethanol enters into a condensation reaction with benzoin in the presence of cobalt, nickel, and copper chlorides to give benzoin isonicotinoylhydrazone (HL), which forms coordination the compounds MLCl·2 H₂O (M = Co, Ni, and Cu) with these metal ions. In the presence of amines (A = C₅H₅N, 3- and 4-CH₃C₅H₄N) this reaction yields complexes MA₂LCl, whereas replacement of chlorides by acetates results in formation of ML₂·n H₂O (n = 0, 2). The complexes synthesized have a pseudooctahedral structure of the coordination polyhedra. The Schiff's base HL behaves in these complexes as a tridentate monobasic O,N,O ligand. Thermolysis of the compounds involves the stages of dehydration, deamination, and exhaustive thermal decomposition. Kinetic parameters for the first stage of the pyrolysis of the complexes have been calculated.