High resolution multi wavelength study of active galaxies This PhD thesis presents a study of active galaxies carried out from cm to mm wavelengths with high angular resolution. The mechanism of the activity in these objects is supposed to be strongly correlated with the accretion of matter onto a super massive black hole in their centres. One approach to increase the understanding of these highly interesting sources is to observe and analyse the molecular gas. The characteristics of its distribution and dynamics are indispensible diagnostic tools to investigate the accretion processes at different angular scales. A second approach is the study of emission originating in the direct vicinity of the black hole such as non thermal radio emission. To account for different activity levels five objects were chosen ranging from nearby Low Luminosity Active Galaxies (LLAGs; NGC3718 at z=0.003 and NGC1068 at z=0.004) to higher redshifted High LAGs (HLAGs; HE1029 1831 at z=0.039 3C48 at z=0.367 and Q0957+561 at z=1.414). The first two sources are part of the NU(clei of) GA(laxy) project that aims at analysing the distribution and kinematics of the molecular gas at high angular resolution sensitivity in a sample of 30 nearby LLAGs. HE1029 1831 is part of a complementary sample of nearby HLAGs with similar aims. All sources were observed in carbon monoxide (CO) known to be a good molecular gas tracer with the IRAM Plateau de Bure Interferometer (PdBI) providing high sensitivity and high angular resolution. CO emission was detected in all five galaxies. In NGC3718 the molecular gas disk having roughly two hundred million solar masses is highly warped. The distribution of the gas reveals large scale asymmetries witnessing a possible tidal tail interaction with a close companion and as well small scale asymmetries most likely tracing accretion onto the nucleus ...