This paper investigates the problem of Maximum Common Connected Subgraph (MCCS) which is not necessarily an induced subgraph. This problem has received little attention in the literature which is mainly devoted to the MCIS problem. Two reductions of the MCCS problem to a MCCIS problem are explored: a classic method based on linegraphs and an original approach using subdivision graphs. Then we propose a method to solve MCCS that searchs for a maximum clique in a compatibility graph. To compare with backtrack approach we explore the applicability of Constraint Satisfaction framework to the MCCS problem for both reductions.