Context : There is a lack of state-of-the-art information on very young open clusters , with implications for determining the structure of the Galaxy .

Aims : Our main objective is to study the timing and location of the star formation processes which yielded the generation of the giant HII region Sh 2-284 .
This includes the determination of different physical variables of the stars , such as distance , reddening , age and evolutionary stage , including pre-main-sequence ( PMS ) stars .

Methods : The analysis is based on UBVR _ { C } I _ { C } CCD measurements of a field of 6.5 ’ \times 6.5 ’ containing the cluster , and JHK _ { s } photometry in the 3.5 ’ \times 3.5 ’ subfield , centered in the apparent higher condensation .
The determination of cluster distance , reddening and age is carried out through comparison with ZAMS , post-MS and PMS isochrones .
The reference lines used are obtained from theoretical post-MS and PMS isochrones from the Geneva and Yale groups , for metalicity Z=0.004 , in agreement with the spectroscopic metallicity determination published for several cluster members .

Results : The results amount to E ( B-V ) =0.78 \pm 0.02 , DM=12.8 \pm 0.2 ( 3.6 kpc ) , LogAge ( yr ) =6.51 \pm 0.07 ( 3.2 Myr ) .
The distance result critically depends on the use of low metallicity ZAMS and isochrones .
A PMS member sequence is proposed , with an age of LogAge ( yr ) =6.7 \pm 0.2 ( 4.7 Myr ) which is therefore coeval within the errors with the post-MS cluster age .
The mass function for this population in the mass range above 1.3-3.5 M _ { \odot } is well fitted by a Salpeter mass function .
The presence of a different star generation in the cluster with a distinctly older age , around 40 Myr , is suggested .
On the other hand , the NIR photometry results indicate a large number of sources with ( H-K _ { s } ) excess , practically distinct from the optical PMS candidate members .

Conclusions : The analysis of our deep UBVRIJHK photometry of Dolidze 25 therefore reveals a young cluster with coeval MS and PMS populations of age 3.2-5 Myr .
In addition , a distinctly older cluster member population of age 40 Myr is suggested .
The distance determined for the cluster from quantitative fits to ZAMS and isochrones is distinctly lower than previously published values .
This result originates in the consistent use of low metallicity models for ZAMS fitting , applying published metallicity values for the cluster