Various fluidic techniques can employ ducting structures, such as microstructures, that extend between other components, such as plate-like structures. A ducting structure can, for example, include an inlet opening toward or near one plate-like structure, an outlet opening toward or near another plate-like structure, and a duct in which fluid flows after being received through the inlet opening and before being provided through the outlet opening. In some implementations, a ducting structure is photo-defined, such as by exposing a photoimageable structure and then removing either exposed or unexposed regions. In some implementations, a ducting structure is a freestanding polymer microstructure. In some implementations, ducting structures are microstructures that extend approximately the same length between first and second plate-like structures, and have a ratio of length to maximum cavity diameter of approximately two or more. A printhead implementation includes an array of such microstructures supported between drive side and drop side assemblies.