PURPOSE: To provide microcapsules that contain a specified compound held in an organic cosolvent vehicle capable of forming a colored complex with a transition metal salt, have good image-forming properties, and are useful for carbon-less copies, etc.

CONSTITUTION: The microcapsules contains a composition, which comprises preferably 0.2-10.0 wt.%, based on capsule contents, of an ethanedimidic acid bis[(arylalkylidene)hydrazide] compound shown by the formula (wherein R1 represents an aryl and alkoxyacetyl; R2-R4 separately represent H, an alkyl, aryl, or R1), which is held in an organic cosolvent vehicle capable of forming a colored complex with a transition metal salt such as nickel 2-ethylhexanoate.