We review the physical and cosmological consequences of two possible electromagnetic couplings to the dark sector: (I.) A newtural 
lightest dark-matter particle (LDP) with nonzero electric and/or magnetic dipole moments and (II.) a charged next-to-lightest 
dark-matter particle (NLDP) which decays to a netural LDP.  For scenario (I.) we find that a relatively light particle with mass 
between a few MeV and a few GeV and an electric or magnetic dipole as large as $\sim 3 \times 10^{-16}e$~cm (roughtly $.16
times 10^{-5}\,\mu_B$) satisfies experimental and observational bounds.  In scenario (II.), we show that charged-particles decaying in 
the early Universe result in a suppression of the small-scale matter power spectrum on scales that enter the horizon prior to decay.  
This leads to either a cutoff in the matter power spectrum, or if the charged fraction is less than unity, an effect in the power 
spectrum that might resemble a running (scale-dependent) spectral index in small-scale data.  If this scenario is realized in nature 
new quasistable charged particles might be produced at future colliders.