A method of depositing a film of a metal chalcogenide including the steps of: contacting an isolated hydrazinium-based precursor of a metal chalcogenide and a solvent having therein a solubilizing additive to form a solution of a complex thereof; applying the solution of the complex onto a substrate to produce a coating of the solution on the substrate; removing the solvent from the coating to produce a film of the complex on the substrate; and thereafter annealing the film of the complex to produce a metal chalcogenide film on the substrate. Also provided is a process for preparing an isolated hydrazinium-based precursor of a metal chalcogenide as well as a thin-film field-effect transistor device using the metal chalcogenides as the channel layer.