An exemplary printable composition of a liquid or gel suspension of diodes comprises a plurality of diodes, a first solvent and/or a viscosity modifier. In other exemplary embodiments a second solvent is also included, and the composition has a viscosity substantially between about 100 cps and about 25,000 cps at about 25° C. In an exemplary embodiment, a composition comprises: a plurality of diodes or other two-terminal integrated circuits; one or more solvents comprising about 15% to 99.9% of any of N-propanol, isopropanol, dipropylene glycol, diethylene glycol, propylene glycol, 1-methoxy-2-propanol, N-octanol, ethanol, tetrahydrofurfuryl alcohol, cyclohexanol, and mixtures thereof; a viscosity modifier comprising about 0.10% to 2.5% methoxy propyl methylcellulose resin or hydroxy propyl methylcellulose resin or mixtures thereof; and about 0.01% to 2.5% of a plurality of substantially optically transparent and chemically inert particles having a range of sizes between about 10 to about 50 microns.