Abstract. In this colloquium, I will present several key results of my research projects that have been mainly on AGN and star forming galaxies. Firstly I will present the results of my work in which I studied the WISE properties of complete samples of radio-loud AGN (Gurkan et al. 2014). In the second part, I will talk about the stacking analysis that I conducted for comparing star formation properties of radio-loud and radio-quiet AGN samples (Gurkan et al. 2015). Later on, I will briefly mention the LOFAR survey and cataloguing of radio sources (Hardcastle & Gurkan et al. 2016). Finally, I will share the latest results of the study in which I explored the relation between low frequency radio luminosity and star formation rates of star forming galaxies using the data taken by LOFAR (Gurkan et al. in prep.).