Printed circuit substrates and electrical assemblies including a conductive composition are disclosed. The printed circuit substrate and the electrical assembly embodiments comprise a first conducting region and a second conducting region. A dielectric layer is disposed between the first and second conducting regions. An aperture is disposed in the dielectric layer and a via structure including the conductive composition is disposed in the aperture. The conductive composition is preferably in a cured state and electrically communicates with the first and second conducting regions. In preferred embodiments, the conductive composition comprises conductive particles in an amount of at least about 75 wt. % based on the weight of the composition. At least 50% by weight of the conductive particles have melting points of less than about 400.degree. C. The composition further includes a carrier including an epoxy-functional resin in an amount of at least about 50 wt. % based on the weight of the carrier, and a fluxing agent in an amount of at least about 0.1 wt % based on the weight of the carrier. The epoxy functional resin can have a viscosity of less than about 1000 centipoise at 25.degree. C.